Unauthorized Immigration to the United States: Annual Estimates and Components of Change, by State, 1990 to 2010

doi:10.1111/imre.12022

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Int Migr Rev. Author manuscript; available in PMC 2014 Jun 1.

Published in final edited form as:

Int Migr Rev. 2013 Jun 1; 47(2): 296–329.

Published online 2013 Feb 15. doi: 10.1111/imre.12022

PMCID: PMC3744247

NIHMSID: NIHMS468176

PMID: 23956482

Unauthorized Immigration to the United States: Annual Estimates and Components of Change, by State, 1990 to 2010

Robert Warren and John Robert Warren

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Abstract

We describe a method for producing annual estimates of the unauthorized immigrant population in the United Sates and components of population change, for each state and D.C., for 1990 to 2010. We quantify a sharp drop in the number of unauthorized immigrants arriving since 2000, and we demonstrate the role of departures from the population (emigration, adjustment to legal status, removal by the Department of Homeland Security (DHS), and deaths) in reducing population growth from one million in 2000 to population losses in 2008 and 2009. The number arriving in the U.S. peaked at more than one million in 1999 to 2001, and then declined rapidly through 2009. We provide evidence that population growth stopped after 2007 primarily because entries declined and not because emigration increased during the economic crisis. Our estimates of the total unauthorized immigrant population in the U.S. and in the top ten states are comparable to those produced by DHS and the Pew Hispanic Center. For the remaining states and D.C., our data and methods produce estimates with smaller ranges of sampling error.

Few demographic estimates diverge as widely as do those pertaining to the size of America’s unauthorized immigrant population. Highly publicized estimates of the total number of unauthorized immigrants residing in the U.S. in recent years range from 10.8 million (Hoefer, Rytina and Baker 2011) to 13 million (Martin and Ruark 2011) to 20 million (Elbel 2007; Justich and Ng 2005).^¹ Likewise, recent estimates of the gross annual number of unauthorized immigrants entering the U.S. range from 300,000 (Passel and Cohn 2010) to a million (Smith 2011)^². Few other demographic estimates diverge as widely or receive so much public attention.

One reason that these diverging demographic estimates generate so much public attention is that they inform any number of contentious public policy discussions at the national and state levels. Should the U.S. grant amnesty to unauthorized immigrant workers? Should we support unauthorized immigrants who came to the U.S. as small children if they wish to attend college or serve in the U.S. armed forces? Should we do more to enforce immigration laws, particularly along the U.S.-Mexico border? Answers to these questions depend in part on the size of the unauthorized immigrant population—at both the national and state levels—and/or on the number of unauthorized immigrants who enter and leave the country each year. Disagreement about those numbers fuels disagreement on these and other contentious policy matters.

Beyond these several policy considerations, estimates of the unauthorized immigrant population are also relevant for academic and applied research on the changing composition and characteristics of the U.S. population. What are the economic costs to native-born workers of unauthorized immigration? How many children should a public school district expect to serve in coming years? How has the racial/ethnic composition of America changed in recent years, and what are the social and economic implications of those changes? How can city planning offices effectively forecast demand on local government services? What are the social and economic predictors of the size and character of migration streams across international borders? The answers to these sorts of questions also depend on demographic estimates of the size of America’s unauthorized immigrant population.

Although one particular estimate—the total number of unauthorized immigrants residing in the U.S.—generates the most attention, there are important policy and research questions that require more detailed and disaggregated estimates. For example, we believe that it is just as important to understand net annual change in the size of that population, as well as the components of that change. This requires information about how many unauthorized immigrants enter the U.S. each year and how many depart via removal by the Department of Homeland Security (DHS), voluntary emigration, or death. It is also important to understand where unauthorized immigrants come from, what their destination states are, and how these patterns have changed over time. In this article, we describe a method for producing reliable annual estimates of the size of the unauthorized immigrant population and of the components of change in the size of that population, all disaggregated by state. Our methods improve upon other available estimates, provide more useful levels of statistical disaggregation, and can be replicated going forward at the national and state levels.

Our estimate of the total size of the unauthorized immigrant population in the United States—11.7 million as of January 2010—does not differ markedly from other recent estimates using similar data and methods (e.g., Hoefer, Rytina and Baker 2011; Passel and Cohn 2011). However, our estimates allow unique assessments of trends over time in the size of that population and of the component processes generating those trends. For example, we demonstrate below that the declining size of the unauthorized immigrant population in recent years has occurred not just because of rapidly declining inflows (i.e., immigrants entering without inspection or overstaying their visas) but also because the number departing from the population is large and increasing. What is more, we demonstrate important heterogeneity across states in these patterns. Finally, as we explain below, our estimates are subject to less sampling error than other recently published estimates.

Review and Critique of Early Estimates

Early estimates of the number of unauthorized immigrants residing in the U.S. were based on strong assumptions and the creative use of very limited data (for reviews, see Donato and Armenta 2011; Espenshade 1995; Siegel, Passel and Robinson 1980). For example, Robinson (1980) began with the estimated number of foreign-born Latinos counted in the 1950 through 1970 decennial censuses and a 1975 intercensal enumeration; used age-specific mortality rates to compute the expected numbers of deaths that should have been observed in various geographic areas; compared those expected numbers of deaths to the actual numbers of deaths records in the vital statistics system; and assumed that the difference between those figures represented the number of unauthorized (Latino) immigrants. As the author notes, this procedure relies on the now discredited assumption that few unauthorized immigrants are counted in federal censuses and the assumption that most of their deaths are reflected in the vital statistics system. Another example: Bean et al. (1983) based their estimates of the number of unauthorized Mexican immigrants on sex ratios observed in the 1980 Mexican census and on assumptions about the gender composition of those immigrants, the sex ratio at birth of Mexican babies, and the undercount of men in the Mexican census. See Bos (1984) and Hill (1985) for a discussion of the methodological challenges faced in many of these pioneering efforts.

Early estimates of the number of unauthorized immigrants entering the U.S. also relied on the use of limited data and on important assumptions (Espenshade 1995; Frisbie 1975; Heer 1979). For example, a number of observers have estimated the probability that an undocumented migrant is apprehended along the U.S.-Mexico border and then combined that with data on the annual number of such apprehensions to produce an estimate of the annual gross flow of undocumented migrants from Mexico (e.g., Espenshade 1990; Massey and Singer 1995). The quality of such estimates depends on the questionable accuracy of apprehension probabilities; in any case, these estimates have been produced only episodically and then only for Mexico.

Review of Recent Estimates

In recent years, virtually all systematic estimates have been based on some form of the residual method^³ , a variant of capture-recapture and dual system estimation procedures used in demography and elsewhere (e.g., Sekar and Deming 1949; Shryock, Siegel and Associates 1973). In general, this method involves comparing the total number of foreign-born people to the number of authorized immigrants. The difference between these figures (perhaps after some adjustments) is an estimate of the number of unauthorized immigrants. As reviewed by Bos (1984), Hill (1985), and Passel (1986), estimates based on the residual method are sensitive to how “authorized” and “unauthorized” immigrants are defined and counted. Some foreign-born people—such as students or tourists who overstay their visas—were authorized to enter the U.S. upon arrival, but should not necessarily be counted as authorized immigrants. Others—such as asylees and parolees who have work authorization but who have not adjusted to permanent resident status and aliens who are allowed to remain and work in the United States under various legislative provisions—may have entered the U.S. without authorization, but should not necessarily be classified as unauthorized immigrants.

Lancaster and Scheuren (1977) were among the first to use the residual method to estimate the number of unauthorized immigrants residing in the United States. They began with an estimate of the size of the total civilian non-institutionalized adult population based on matched March 1973 Current Population Survey (CPS) and administrative record data (80.2 million), subtracted from that an estimate of the size of the legal civilian non-institutionalized adult population based on adjusted 1970 Census data (76.3 million), and arrived at an estimate of the number of illegal immigrant adults in April 1973 (3.9 million). More recently, Warren and Passel (1987) and Passel and Woodrow (1984) estimated the number of unauthorized immigrants counted in the 1980 Census (2.06 million) by comparing the non-naturalized foreign-born population in the 1980 Census (7.44 million) to the non-naturalized legally resident immigrant population at the time of the 1980 Census (5.38 million). Using similar methods, Woodrow and Passel (1990) used 1986 and 1988 CPS data to show that the number of unauthorized immigrants in the U.S. declined precipitously (from 3.16 million to 1.91 million) after IRCA. Likewise, Warren (2003) used residual methods to estimate that about 7 million unauthorized immigrants lived in the U.S. in January 2000.

The residual method has also been used to estimate the annual number of unauthorized immigrants entering (and remaining) in the U.S. and the annual net change in the size of that population. These figures are based on (1) the estimated total number of unauthorized immigrants after disaggregating by year of entry; (2) information from administrative records on annual numbers of legal entrants and removals (e.g., U.S. Department of Homeland Security 2010); and (3) estimated mortality and emigration rates (e.g., Van Hook and Zhang 2011). For example, Woodrow and Passel (1990) used this method to conclude that the average annual net increase in the number of unauthorized immigrants was almost unchanged in the two years after IRCA (246,000 per year) compared to the years immediately before it (218,000 per year).

Two ongoing sets of published reports provide estimates of the size and characteristics of the unauthorized immigrant population. Both are based on the residual method. However, despite their conceptual and technical similarities, each is limited in important ways. Both have methodological limitations, but more importantly, neither provides adequately disaggregated estimates. A central goal of the current article is to overcome these limitations and to provide estimates that are more useful for applied and academic purposes.

First, since 2005, Passel, Cohn and colleagues at the Pew Hispanic Center (hereafter, Pew) have issued reports on the size and characteristics of the unauthorized immigrant population (e.g., Passel 2005; Passel and Cohn 2009; Passel and Cohn 2011). Their estimates begin with the total number of foreign-born people residing in the U.S. as reflected in the Annual Social and Economic Supplement to the March Current Population Survey (CPS). They subtract from that figure the estimated number of legal residents based on data collected by DHS and other government agencies; for their purposes, these include naturalized citizens, legal permanent residents, refugees, asylees and parolees; and legal temporary residents (e.g., students and workers in some high technology industries). Some of their reports include estimates of annual net change in the size of the unauthorized immigrant population (Passel and Cohn 2008; Passel and Cohn 2010). The Pew estimates are typically disaggregated by state of residence, geographic regions of origin, and five-year periods of entry.

Second, in recent years the Department of Homeland Security’s (DHS) Office of Immigration Statistics (OIS) has also issued reports on the size and characteristics of the unauthorized immigrant population (e.g., Hoefer, Rytina and Baker 2011; Hoefer, Rytina and Campbell 2006). Their estimates begin with the total number of foreign-born people residing in the U.S. as reflected in the annual American Community Survey (ACS). Like the Pew estimates, they subtract from that figure the estimated number of legal residents based on data collected by DHS and other government agencies; these include naturalized citizens, legal permanent residents, asylees, refugees, and nonimmigrants (e.g., students and temporary workers). The OIS estimates are typically disaggregated by state of residence, region and country of origin, and period of entry. These reports have typically included a statement about the average annual net change in the size of the unauthorized immigrant population over a period of several years.

The Pew and OIS estimates are similar at the national level and for larger states. For example, their estimates of the total size of the unauthorized immigrant population in early 2010 were 11.2 million and 10.8 million, respectively (Hoefer, Rytina and Baker 2011; Passel and Cohn 2011). Both estimated that California was home to 2.6 million unauthorized immigrants.

Critique of Recent Estimates

The Pew and OIS estimates are based on methods that, in significant aspects, are similar to our own, and they are useful for a number of academic and policy applications. However, in some important areas – estimates for states with relatively smaller populations, analysis of long-term trends for every state, and estimates derived separately for arrivals and departures — our estimates should prove to be more useful. Below we review four conceptual and technical differences between those estimates and ours.

First, neither the Pew nor the OIS reports routinely disaggregate annual net change in the size of the unauthorized immigrant population into its component parts: inflows and outflows. Net change is a function of people entering that population (mainly via “entering without inspection” or overstaying temporary visas) and leaving that population (via removal by DHS, death, adjusting to authorized status, or voluntary emigration). Both Pew and OIS report annual net change, and in some reports, Pew describes total inflows for selected years (e.g., Passel and Cohn 2010: iii). However, there is a considerable amount of policy and research interest in the components of entry and exit from the population of authorized immigrants. How many unauthorized immigrants enter the U.S. each year, either by “entering without inspection” or by overstaying a student, tourist, or other temporary visa? How many unauthorized residents are removed by DHS? How many simply leave voluntarily? How many adjust to lawful status? Without access to disaggregated components of change of this sort, it becomes difficult to interpret net change in the total size of the unauthorized immigrant population. For example, Pew and OIS each reported that the size of that population declined between 2008 and 2009, by 500,000 (Passel and Cohn 2011) and 800,000 (Hoefer, Rytina and Baker 2011), respectively. Did this decline happen mainly because fewer people entered the country without authorization, because fewer people who were admitted temporarily overstayed their visas, because of a growing numbers of removals by DHS, or because of increasing rates of emigration? Likewise, what are the relative contributions of these components of change to the increase in the overall size of the unauthorized immigrant population in earlier years? The Pew and OIS reports provide very limited evidence regarding these questions, despite their fundamental importance for policy and research purposes.

Second, like OIS, we use data from the American Community Survey; the Pew estimates are based on data from the CPS. The relatively small size of the CPS sample—even when expanded somewhat for the March supplement—yields substantially larger ranges of sampling error in the Pew estimates. For example, the 90% confidence interval for Pew’s CPS-based estimate of the size of the unauthorized immigrant population in 2010 was 11.2 million ± 500,000 (Passel and Cohn 2011: Table 2). In contrast, the 90% confidence interval for the parallel OIS figure—based on the ACS, which includes 30 times as many observations as the CPS—was 10.8 million ± 149,000 (Hoefer, Rytina and Baker 2011: 2). This uncertainty in the CPS-based estimates leads the authors of the Pew reports to aggregate data in a way that obscures potentially important detail. For example, the authors sometimes aggregate across states (as described below) and combine countries of origin in their reports such that all unauthorized immigrants are classified as originating from (1) Mexico, (2) other Latin American countries, (3) Asia, (4) Europe or Canada, or (5) elsewhere. Statistical uncertainty with CPS-based estimates also leads to problems with statistical power when analyzing trends over time. For instance, the authors of the Pew reports describe the decline in the number of unauthorized immigrants between 2007 (12.0 million) and 2009 (11.1 million). This decline of nearly one million was not statistically significantly different from zero (Passel and Cohn 2011: Table 2).

Table 2

Annual Estimates of the Foreign-born Population Residing in the United States, by Legal Status and Year of Entry: 1990 to 1999

	Foreign-born Population in January 2000				Unauthorized Immigrant Population in January 2000	Left the Unauthorized Immigrant Population (via Emigration, Removal by DHS Adjustment to Lawful Status, or Death)
Year of Entry	Total (2000 Census)	Legally Resident	Unauthorized	Undercount	Unauthorized Immigrant Population in January 2000	1999	1998	1997	1996	1995	1994	1993	1992	1991	1990	Entry cohorts

	(1)	(2)	(3)= (1)-(2)	(4)	(5)= 3+4¹	(6)	(7)	(8)	(9)	(10)	(11)	(12)	(13)	(14)	(15)	(16)= Σ(5–15)¹
Total	12,590	6,851	5,741	609	8,600	358	338	311	284	251	233	229	220	197	181
1999	1,868	824	979	127	1,106	26	-	-	-	-	-	-	-	-	-	1,132
1998	1,463	680	793	97	889	44	20	-	-	-	-	-	-	-	-	954
1997	1,229	670	604	70	674	31	37	16	-	-	-	-	-	-	-	759
1996	1,171	655	582	63	646	27	31	36	15	-	-	-	-	-	-	756
1995	1,371	634	617	63	680	27	30	33	35	16	-	-	-	-	-	822
1994	1,155	678	505	49	554	23	25	27	27	30	14	-	-	-	-	700
1993	1,033	704	381	35	416	18	20	21	22	22	25	12	-	-	-	557
1992	1,094	705	368	32	400	17	19	21	21	21	22	25	12	-	-	559
1991	988	625	415	34	449	20	21	22	23	23	24	25	28	15	-	649
1990	1,219	677	498	39	536	31	30	27	27	27	27	29	31	33	18	816

Pre`90	-	-	-	-	2,250	94	103	107	113	112	121	138	149	149	163	3,500

All numbers in thousands, and rounded independently.

¹Except for the shaded area

Third, neither the Pew nor the OIS figures are disaggregated fully and reliably by state. The OIS reports provide estimates of the size of unauthorized immigrant population only in the 10 states with the largest such populations (e.g., Hoefer, Rytina and Baker 2011: Table 4). Over time, the Pew reports have employed different methods to produce state estimates. In some years, they have used residual methods to directly generate estimates of the size of unauthorized immigrant population only in the several states with the largest such populations. For the remaining states, they have employed some form of averaging across states and/or regression-based estimates. In all years, and even after averaging across multiple years, the Pew estimates for states have wide margins of error; again, this is a function of the relatively small sample sizes in the March CPS. For example, even after averaging across multiple years of CPS data, their 90% confidence interval for the number of unauthorized immigrants in Alabama in 2010 ranged from 75,000 to 160,000 (Passel and Cohn 2011: Table A3).

Table 4

Sensitivity of Estimates of the Size of the Unauthorized Immigrant Population in 2010 to Different Assumptions about Emigration and Undercount Rates

Effects of changing emigration rates by + or − 25%
	Increase rates by 25%		Reduce rates by 25%
	Number	Percent	Number	Percent
Unauthorized Immigrants	−403	−3.40%	431	3.70%
Authorized Immigrants	375	3.20%	−383	−3.30%

Effects of changing undercount rates by + or − 25%

	Increase rates by 25%		Reduce rates by 25%
	Number	Percent	Number	Percent
Unauthorized Immigrants	356	3.00%	−332	−2.80%
Authorized Immigrants	172	1.50%	−159	−1.40%

All numbers in thousands, and rounded independently.

Table A3

Estimates of the Unauthorized Immigrant Population and Annual Components of Population Change, by State: 1990 to 2010

				Left Population
	Population on Jan. 1	Net Change	Entered Pop.	Total Left Pop.	Emigrated	Adjusted	Removed	Died
UNITED STATES
1990	3,500,000	634,935	815,876	180,941	102,648	37,883	25,369	15,041
1991	4,134,935	451,657	648,602	196,945	115,922	35,290	28,568	17,165
1992	4,586,592	338,842	558,601	219,759	124,179	42,925	33,921	18,735
1993	4,925,434	327,496	556,605	229,109	130,175	44,870	34,023	20,041
1994	5,252,930	467,096	700,030	232,934	138,038	38,392	34,921	21,582
1995	5,720,026	570,626	821,533	250,907	149,624	41,900	35,765	23,618
1996	6,290,652	472,185	755,784	283,599	161,052	55,428	41,426	25,693
1997	6,762,838	447,625	758,703	311,078	170,283	54,319	58,954	27,522
1998	7,210,462	616,057	953,591	337,534	181,664	61,448	64,797	29,626
1999	7,826,519	773,482	1,131,520	358,038	197,808	60,393	65,287	34,551
2000	8,600,005	1,020,484	1,389,322	368,838	197,784	72,621	65,279	33,154
2001	9,620,489	638,197	1,145,813	507,616	223,171	176,169	71,191	37,085
2002	10,258,686	433,517	906,295	472,778	237,468	114,927	80,836	39,546
2003	10,692,203	285,752	779,187	493,435	244,470	119,709	88,033	41,223
2004	10,977,956	338,847	812,516	473,669	246,684	84,288	100,363	42,333
2005	11,316,803	397,498	873,134	475,636	250,187	79,037	102,764	43,648
2006	11,714,302	266,996	749,421	482,425	255,867	64,200	117,171	45,187
2007	11,981,297	27,212	558,276	531,064	257,585	94,064	133,190	46,225
2008	12,008,509	(109,690)	439,496	549,186	252,281	100,485	150,079	46,341
2009	11,898,820	(173,804)	384,314	558,118	243,319	104,029	164,839	45,931
2010	11,725,016
ALABAMA
1990	5,000	1,723	2,010	287	160	88	16	23
1991	6,723	1,231	1,533	302	200	62	11	29
1992	7,954	848	1,162	314	225	46	10	33
1993	8,802	964	1,321	357	245	52	24	36
1994	9,766	1,640	2,000	360	277	24	18	41
1995	11,407	2,029	2,472	443	324	43	27	49
1996	13,435	2,344	2,830	486	380	42	6	57
1997	15,780	3,322	3,931	609	456	38	47	68
1998	19,101	4,766	5,546	780	568	104	25	84
1999	23,867	5,471	6,436	965	709	108	31	117
2000	29,339	9,987	11,042	1,055	747	162	32	113
2001	39,326	8,730	10,235	1,505	1,023	273	58	151
2002	48,056	5,871	7,578	1,707	1,251	218	52	185
2003	53,927	3,824	5,678	1,854	1,381	210	55	208
2004	57,751	5,417	7,315	1,898	1,442	169	65	222
2005	63,168	8,603	10,691	2,088	1,550	228	66	243
2006	71,771	7,966	10,277	2,311	1,753	205	77	276
2007	79,737	4,992	7,588	2,596	1,926	276	87	307
2008	84,729	5,039	7,772	2,733	2,000	311	95	327
2009	89,768	5,679	8,539	2,860	2,076	333	105	346
2010	95,448
ALASKA
1990	2,500	563	821	258	77	71	99	11
1991	3,063	485	819	334	93	65	163	13
1992	3,548	390	715	325	104	41	166	15
1993	3,938	205	612	407	111	26	254	16
1994	4,142	191	511	320	113	17	172	17
1995	4,334	95	401	306	114	16	158	17
1996	4,429	(55)	267	322	111	15	178	18
1997	4,374	(44)	268	312	106	14	174	17
1998	4,330	(14)	363	377	103	57	199	17
1999	4,316	101	500	399	103	102	175	19
2000	4,415	(90)	226	316	97	48	154	17
2001	4,325	(146)	202	348	92	100	140	17
2002	4,179	(40)	283	323	86	101	120	16
2003	4,139	140	438	298	84	68	130	16
2004	4,279	414	704	290	88	38	147	17
2005	4,693	871	1,186	315	100	44	153	18
2006	5,565	773	1,140	367	126	47	172	21
2007	6,338	58	499	441	148	72	197	24
2008	6,396	(351)	114	465	147	70	224	25
2009	6,045	(466)	18	484	133	83	244	23
2010	5,579
ARIZONA
1990	89,000	17,866	21,791	3,925	2,627	402	512	384
1991	106,866	14,954	19,643	4,689	3,047	364	829	449
1992	121,820	15,060	20,546	5,486	3,408	428	1,141	509
1993	136,880	16,600	22,547	5,947	3,780	510	1,087	570
1994	153,480	21,980	28,551	6,571	4,251	498	1,176	646
1995	175,460	25,581	32,874	7,293	4,846	591	1,117	739
1996	201,041	21,403	29,622	8,219	5,407	632	1,348	831
1997	222,444	19,390	28,739	9,349	5,855	557	2,025	912
1998	241,834	25,156	35,049	9,893	6,344	666	1,884	999
1999	266,990	30,333	41,030	10,697	6,991	879	1,640	1,188
2000	297,324	19,657	30,278	10,621	7,035	832	1,608	1,146
2001	316,981	11,836	24,830	12,994	7,386	2,763	1,623	1,222
2002	328,818	7,210	19,028	11,818	7,516	1,613	1,421	1,268
2003	336,028	3,222	15,679	12,457	7,492	2,122	1,547	1,296
2004	339,250	3,783	15,710	11,927	7,354	1,500	1,764	1,309
2005	343,033	5,064	16,719	11,655	7,242	1,283	1,806	1,324
2006	348,097	726	12,247	11,521	7,199	919	2,060	1,344
2007	348,823	(5,167)	7,140	12,307	7,041	1,579	2,341	1,347
2008	343,656	(4,132)	8,278	12,410	6,720	1,726	2,637	1,327
2009	339,524	(189)	12,203	12,392	6,455	1,730	2,896	1,312
2010	339,334
ARKANSAS
1990	5,000	2,699	2,961	262	176	50	12	25
1991	7,699	2,298	2,643	345	248	39	24	35
1992	9,996	1,979	2,396	417	306	53	16	43
1993	11,975	1,757	2,254	497	353	67	26	50
1994	13,732	2,218	2,748	530	401	50	21	58
1995	15,950	2,728	3,351	623	464	57	34	68
1996	18,678	2,633	3,392	759	531	112	37	78
1997	21,312	2,544	3,420	876	593	128	67	89
1998	23,855	3,064	4,005	941	659	79	103	100
1999	26,920	3,782	4,803	1,021	742	71	86	122
2000	30,701	7,623	8,824	1,201	750	186	147	118
2001	38,324	5,885	7,625	1,740	954	512	127	148
2002	44,209	4,514	6,287	1,773	1,100	359	144	170
2003	48,722	2,937	4,868	1,931	1,198	389	156	188
2004	51,659	3,659	5,492	1,833	1,245	210	179	199
2005	55,318	4,782	6,717	1,935	1,310	229	183	213
2006	60,100	3,031	5,071	2,040	1,409	191	208	232
2007	63,131	1,859	4,085	2,226	1,452	292	238	243
2008	64,991	2,310	4,583	2,273	1,460	294	268	251
2009	67,301	1,122	3,473	2,351	1,482	315	294	260
2010	68,423
CALIFORNIA
1990	1,474,700	198,763	270,902	72,139	42,075	10,423	13,444	6,198
1991	1,673,463	130,272	206,787	76,515	45,644	9,981	14,049	6,841
1992	1,803,735	79,485	161,524	82,039	47,243	13,531	14,008	7,257
1993	1,883,219	66,838	147,877	81,039	47,768	12,920	12,812	7,540
1994	1,950,057	98,475	179,308	80,833	48,634	10,914	13,425	7,860
1995	2,048,532	122,701	208,343	85,642	50,439	11,741	15,165	8,297
1996	2,171,234	95,274	188,109	92,835	52,185	16,214	15,704	8,733
1997	2,266,508	80,091	181,575	101,484	53,308	19,296	19,790	9,089
1998	2,346,598	111,591	217,529	105,938	54,703	18,184	23,582	9,469
1999	2,458,189	142,446	251,574	109,128	57,054	17,083	24,534	10,457
2000	2,600,636	164,021	276,719	112,698	56,140	22,410	24,115	10,033
2001	2,764,657	68,580	227,278	158,698	59,918	64,076	24,039	10,665
2002	2,833,237	49,460	187,733	138,273	61,287	39,567	26,490	10,930
2003	2,882,696	36,550	177,358	140,808	61,813	39,023	28,851	11,122
2004	2,919,246	64,106	197,053	132,947	61,900	26,890	32,893	11,264
2005	2,983,352	88,973	219,122	130,149	62,707	22,258	33,671	11,513
2006	3,072,325	58,986	190,050	131,064	64,314	16,497	38,396	11,857
2007	3,131,311	(15,914)	129,948	145,862	64,977	25,153	43,647	12,085
2008	3,115,398	(73,487)	77,212	150,699	63,441	26,063	49,169	12,026
2009	3,041,910	(107,510)	43,829	151,339	60,277	25,313	54,003	11,746
2010	2,934,400
COLORADO
1990	30,000	11,575	13,066	1,491	978	230	143	141
1991	41,575	9,277	11,320	2,043	1,273	210	378	182
1992	50,851	8,660	11,188	2,528	1,511	258	542	217
1993	59,512	8,220	11,338	3,118	1,725	336	807	251
1994	67,731	10,770	14,505	3,735	1,968	316	1,162	289
1995	78,502	13,928	18,491	4,563	2,296	492	1,437	338
1996	92,430	13,339	18,546	5,207	2,649	506	1,660	391
1997	105,770	12,076	18,709	6,633	2,973	433	2,784	443
1998	117,846	16,366	23,665	7,299	3,326	688	2,786	499
1999	134,211	19,738	28,549	8,811	3,803	696	3,684	627
2000	153,949	17,146	25,606	8,460	3,826	831	3,209	593
2001	171,095	10,750	21,416	10,666	4,213	2,097	3,697	659
2002	181,845	7,989	18,530	10,541	4,411	1,356	4,073	701
2003	189,834	7,206	18,824	11,618	4,516	1,934	4,436	732
2004	197,040	7,616	18,867	11,251	4,601	834	5,057	759
2005	204,656	6,588	17,990	11,402	4,685	752	5,176	789
2006	211,243	2,856	15,089	12,233	4,744	771	5,903	815
2007	214,099	(2,565)	10,605	13,170	4,700	935	6,710	826
2008	211,534	(6,087)	7,896	13,983	4,497	1,110	7,560	816
2009	205,447	(8,366)	6,066	14,432	4,204	1,131	8,304	793
2010	197,082
CONNECTICUT
1990	19,000	4,479	5,778	1,299	579	514	122	84
1991	23,479	3,015	4,453	1,438	678	499	163	99
1992	26,494	1,391	3,034	1,643	725	552	258	108
1993	27,885	1,271	2,951	1,680	744	608	215	113
1994	29,156	3,523	5,180	1,657	797	531	207	122
1995	32,679	4,766	6,682	1,916	906	651	220	139
1996	37,445	3,595	5,712	2,117	1,012	643	307	155
1997	41,041	4,030	6,222	2,192	1,101	633	288	170
1998	45,070	6,688	9,342	2,654	1,243	770	450	192
1999	51,758	8,881	11,820	2,939	1,455	747	492	245
2000	60,639	20,898	23,770	2,872	1,495	871	273	234
2001	81,537	14,826	19,357	4,531	2,086	1,639	492	314
2002	96,363	7,640	12,582	4,942	2,478	1,100	993	371
2003	104,004	2,063	7,405	5,342	2,632	1,227	1,082	400
2004	106,066	1,467	6,754	5,287	2,608	1,037	1,233	409
2005	107,534	3,055	8,253	5,198	2,566	958	1,260	414
2006	110,589	3,553	8,836	5,283	2,580	836	1,441	426
2007	114,142	1,680	7,463	5,783	2,611	1,097	1,635	440
2008	115,822	(2,293)	3,805	6,098	2,585	1,224	1,843	447
2009	113,528	(4,634)	1,566	6,200	2,440	1,298	2,024	438
2010	108,894
DELEWARE
1990	3,000	796	962	166	92	45	16	13
1991	3,796	680	900	220	113	61	30	16
1992	4,475	933	1,158	225	134	54	18	19
1993	5,408	978	1,215	237	159	44	11	23
1994	6,386	860	1,122	262	182	32	22	27
1995	7,246	802	1,118	316	201	37	47	30
1996	8,048	750	1,097	347	218	39	57	33
1997	8,798	1,037	1,399	362	238	30	57	37
1998	9,835	1,355	1,852	497	269	72	115	41
1999	11,190	1,498	2,060	562	305	104	102	51
2000	12,687	758	1,315	557	309	101	99	49
2001	13,445	2,276	3,061	785	321	288	124	52
2002	15,721	2,777	3,531	754	382	199	113	61
2003	18,498	1,226	2,095	869	454	220	123	71
2004	19,724	481	1,320	839	477	146	140	76
2005	20,205	991	1,854	863	476	164	145	78
2006	21,196	749	1,623	874	492	138	162	82
2007	21,945	(402)	556	958	499	190	185	85
2008	21,543	(561)	396	957	471	190	212	83
2009	20,982	36	983	947	441	197	228	81
2010	21,018
DISTRICT OF COLUMBIA
1990	15,000	1,253	2,081	828	417	224	125	62
1991	16,253	753	1,548	795	432	218	79	66
1992	17,005	266	1,105	839	433	251	87	68
1993	17,271	187	978	791	425	214	84	68
1994	17,458	279	1,017	738	417	181	71	69
1995	17,737	395	1,186	791	414	230	75	71
1996	18,133	314	1,186	872	414	282	104	72
1997	18,447	294	1,163	869	412	208	176	73
1998	18,740	696	1,529	833	415	228	115	75
1999	19,436	1,207	1,991	784	433	191	77	83
2000	20,644	675	1,526	851	431	276	64	80
2001	21,319	(37)	1,019	1,056	445	487	42	82
2002	21,282	(358)	553	911	440	315	74	82
2003	20,925	(84)	920	1,004	424	419	80	81
2004	20,841	533	1,325	792	419	202	91	80
2005	21,374	342	1,132	790	430	183	94	83
2006	21,716	947	1,748	801	435	174	108	84
2007	22,663	1,090	1,987	897	458	228	123	87
2008	23,753	(57)	969	1,026	485	313	136	92
2009	23,696	(495)	540	1,035	477	317	150	91
2010	23,201
FLORIDA
1990	239,000	42,475	53,964	11,489	6,981	2,701	783	1,024
1991	281,475	35,563	47,736	12,173	7,940	2,383	674	1,175
1992	317,038	32,900	45,878	12,978	8,712	2,293	663	1,309
1993	349,939	31,335	45,776	14,441	9,401	2,943	662	1,436
1994	381,274	39,331	54,538	15,207	10,167	2,750	716	1,573
1995	420,605	43,491	60,263	16,772	11,107	3,307	621	1,736
1996	464,096	28,962	48,015	19,053	11,857	4,383	932	1,880
1997	493,058	22,858	43,460	20,602	12,264	4,670	1,685	1,984
1998	515,916	41,455	63,281	21,826	12,871	4,884	1,961	2,110
1999	557,371	62,661	86,497	23,836	14,106	5,267	1,980	2,484
2000	620,034	106,378	132,276	25,898	14,243	6,824	2,441	2,390
2001	726,412	75,246	111,110	35,864	17,073	13,318	2,673	2,800
2002	801,659	56,093	89,847	33,754	18,927	7,800	3,938	3,090
2003	857,751	39,761	74,928	35,167	20,081	7,490	4,290	3,306
2004	897,512	36,437	70,840	34,403	20,688	5,365	4,890	3,460
2005	933,949	37,450	73,525	36,075	21,163	6,307	5,004	3,601
2006	971,398	22,265	58,450	36,185	21,725	5,004	5,710	3,746
2007	993,663	(4,830)	36,504	41,334	21,823	9,189	6,489	3,833
2008	988,833	(1,978)	39,039	41,017	21,122	8,771	7,309	3,815
2009	986,855	14,316	55,951	41,635	20,527	9,270	8,029	3,809
2010	1,001,171
GEORGIA
1990	34,000	18,586	20,411	1,825	1,198	311	145	170
1991	52,586	14,214	16,438	2,224	1,669	210	111	234
1992	66,801	13,396	16,029	2,633	2,038	162	145	288
1993	80,197	15,448	18,488	3,040	2,411	124	161	344
1994	95,645	20,256	23,895	3,639	2,880	92	253	414
1995	115,901	23,587	28,072	4,485	3,461	277	247	500
1996	139,488	21,188	26,424	5,236	4,030	228	391	588
1997	160,676	21,451	27,664	6,213	4,546	292	704	672
1998	182,127	30,378	37,741	7,363	5,195	625	769	774
1999	212,505	38,099	46,895	8,796	6,088	755	953	1,000
2000	250,604	37,082	46,354	9,272	6,266	1,165	876	965
2001	287,686	26,855	39,043	12,188	7,146	2,374	1,560	1,108
2002	314,541	21,983	33,311	11,328	7,703	1,631	782	1,212
2003	336,524	18,969	30,442	11,473	8,081	1,244	852	1,297
2004	355,493	18,358	30,192	11,834	8,347	1,146	971	1,370
2005	373,851	14,904	27,679	12,775	8,590	1,749	994	1,441
2006	388,755	7,044	19,999	12,955	8,747	1,575	1,133	1,499
2007	395,800	2,481	16,188	13,707	8,671	2,222	1,287	1,527
2008	398,281	1,198	14,797	13,599	8,462	2,150	1,450	1,537
2009	399,479	(2,603)	10,963	13,566	8,227	2,201	1,596	1,542
2010	396,876
HAWAII
1990	5,000	1,185	1,740	555	156	366	11	23
1991	6,185	939	1,484	545	185	232	102	27
1992	7,123	669	1,406	737	208	133	367	30
1993	7,792	588	1,167	579	219	73	255	32
1994	8,380	270	825	555	225	63	233	34
1995	8,650	156	764	608	225	68	280	35
1996	8,806	144	866	722	224	129	333	36
1997	8,950	457	1,244	787	230	94	426	37
1998	9,407	945	1,738	793	247	255	252	40
1999	10,352	1,111	1,941	830	275	268	239	47
2000	11,463	631	1,525	894	273	287	290	44
2001	12,094	916	1,883	967	286	398	236	47
2002	13,010	1,114	2,126	1,012	309	350	303	50
2003	14,124	1,108	2,262	1,154	338	431	330	54
2004	15,232	655	1,950	1,295	367	494	375	59
2005	15,887	(199)	907	1,106	383	277	385	61
2006	15,688	(148)	945	1,093	369	224	439	60
2007	15,541	194	1,526	1,332	357	416	500	60
2008	15,734	61	1,407	1,346	357	367	562	61
2009	15,795	347	1,810	1,463	353	432	617	61
2010	16,142
IDAHO
1990	10,000	1,715	2,144	429	290	36	60	43
1991	11,715	1,590	2,131	541	332	38	122	49
1992	13,306	1,597	2,228	631	370	47	158	56
1993	14,903	1,162	2,013	851	403	78	309	61
1994	16,065	1,144	1,970	826	424	79	257	66
1995	17,210	1,292	2,198	906	449	124	263	71
1996	18,502	854	1,886	1,032	469	126	363	75
1997	19,356	198	1,393	1,195	472	111	535	77
1998	19,554	557	1,875	1,318	472	195	572	79
1999	20,110	1,264	2,624	1,360	489	152	631	88
2000	21,376	4,301	5,652	1,351	477	222	569	82
2001	25,677	3,207	4,811	1,604	598	379	527	99
2002	28,885	1,605	3,282	1,677	683	209	674	111
2003	30,490	865	2,776	1,911	713	346	734	118
2004	31,355	1,698	3,600	1,902	723	222	836	121
2005	33,053	2,104	4,034	1,930	758	188	857	127
2006	35,156	656	2,711	2,055	804	138	977	136
2007	35,812	(1,152)	1,114	2,266	806	211	1,111	138
2008	34,660	(1,501)	871	2,372	754	233	1,251	134
2009	33,159	(1,030)	1,414	2,444	694	246	1,376	128
2010	32,129
ILLINOIS
1990	195,000	34,694	44,934	10,240	5,711	1,737	1,955	837
1991	229,694	24,771	35,616	10,845	6,431	1,687	1,775	953
1992	254,465	18,564	31,288	12,724	6,891	2,550	2,243	1,040
1993	273,029	18,761	31,704	12,943	7,229	2,920	1,681	1,113
1994	291,791	28,444	41,502	13,058	7,718	2,466	1,671	1,204
1995	320,234	36,187	49,396	13,209	8,458	2,342	1,081	1,329
1996	356,421	29,321	44,221	14,900	9,197	3,123	1,122	1,458
1997	385,741	27,323	43,889	16,566	9,780	3,288	1,927	1,571
1998	413,065	35,508	53,115	17,607	10,443	3,492	1,978	1,694
1999	448,573	40,150	58,886	18,736	11,288	3,651	1,839	1,957
2000	488,724	50,219	68,725	18,506	11,242	3,391	1,989	1,884
2001	538,943	30,313	55,820	25,507	12,428	8,080	2,921	2,078
2002	569,256	17,847	41,504	23,657	13,039	5,417	3,005	2,195
2003	587,104	4,549	28,582	24,033	13,227	5,269	3,273	2,264
2004	591,653	2,811	26,406	23,595	12,995	4,587	3,731	2,282
2005	594,464	8,972	31,837	22,865	12,721	4,030	3,821	2,294
2006	603,436	4,162	27,138	22,976	12,682	3,609	4,356	2,329
2007	607,598	(5,196)	18,581	23,777	12,520	3,961	4,950	2,345
2008	602,402	(7,618)	16,741	24,359	12,089	4,368	5,576	2,326
2009	594,784	(10,135)	14,380	24,515	11,628	4,464	6,127	2,297
2010	584,649
INDIANA
1990	10,000	4,308	4,895	587	335	161	43	48
1991	14,308	3,119	3,821	702	440	143	57	62
1992	17,428	2,468	3,260	792	511	150	58	73
1993	19,896	2,541	3,458	917	571	205	58	83
1994	22,437	3,748	4,662	914	648	109	62	95
1995	26,185	4,545	5,572	1,027	754	126	35	112
1996	30,729	4,711	5,888	1,177	871	126	50	130
1997	35,441	6,031	7,368	1,337	1,008	82	97	151
1998	41,471	8,324	10,125	1,801	1,200	347	74	179
1999	49,795	10,371	12,505	2,134	1,454	342	98	240
2000	60,166	10,051	12,222	2,171	1,517	299	123	232
2001	70,217	7,135	9,990	2,855	1,763	614	208	270
2002	77,352	5,144	8,261	3,117	1,917	540	362	298
2003	82,496	3,686	7,022	3,336	2,005	619	394	318
2004	86,182	5,145	8,287	3,142	2,046	313	451	332
2005	91,326	6,754	9,988	3,234	2,128	294	461	352
2006	98,080	3,756	7,266	3,510	2,258	348	526	378
2007	101,836	1,370	5,085	3,715	2,292	432	598	393
2008	103,206	2,146	6,000	3,854	2,252	532	672	398
2009	105,352	2,515	6,416	3,901	2,240	516	739	407
2010	107,867
IOWA
1990	5,000	1,406	1,682	276	155	91	8	22
1991	6,406	867	1,312	445	187	96	134	27
1992	7,273	644	1,088	444	204	99	111	30
1993	7,917	876	1,378	502	222	139	108	33
1994	8,793	1,716	2,196	480	255	92	94	38
1995	10,509	2,240	2,768	528	309	90	83	46
1996	12,749	2,388	3,073	685	373	140	118	55
1997	15,137	2,994	3,760	766	445	130	125	65
1998	18,131	3,630	4,540	910	535	159	137	79
1999	21,761	4,284	5,278	994	641	125	123	104
2000	26,044	4,667	5,871	1,204	665	211	228	100
2001	30,711	3,489	5,133	1,644	783	434	309	118
2002	34,200	2,791	4,740	1,949	864	335	618	132
2003	36,992	2,560	4,737	2,177	921	441	673	142
2004	39,552	2,665	4,746	2,081	968	192	769	152
2005	42,216	2,385	4,527	2,142	1,015	177	788	163
2006	44,601	1,589	3,855	2,266	1,052	146	896	172
2007	46,190	642	3,129	2,487	1,063	226	1,019	178
2008	46,833	273	2,907	2,634	1,048	260	1,146	181
2009	47,106	31	2,768	2,737	1,024	271	1,260	182
2010	47,137
KANSAS
1990	13,000	3,338	4,007	669	397	113	101	58
1991	16,338	2,886	3,760	874	482	108	214	70
1992	19,224	2,773	3,845	1,072	556	130	305	81
1993	21,997	2,860	4,044	1,184	625	171	295	92
1994	24,858	3,982	5,135	1,153	710	124	214	106
1995	28,839	4,659	5,886	1,227	820	161	123	122
1996	33,499	3,959	5,507	1,548	928	273	208	140
1997	37,458	4,310	6,007	1,697	1,025	219	297	156
1998	41,768	5,655	7,716	2,061	1,150	376	360	176
1999	47,423	6,615	8,846	2,231	1,305	333	376	217
2000	54,039	7,392	9,753	2,361	1,322	426	405	208
2001	61,431	5,295	8,119	2,824	1,501	788	298	237
2002	66,726	1,482	4,190	2,708	1,613	553	285	257
2003	68,208	(1,085)	1,788	2,873	1,602	699	309	263
2004	67,122	(260)	2,254	2,514	1,516	387	353	259
2005	66,862	1,427	3,870	2,443	1,457	366	363	258
2006	68,289	2,501	4,917	2,416	1,456	285	411	263
2007	70,790	1,574	4,220	2,646	1,490	413	469	273
2008	72,364	1,793	4,620	2,827	1,496	523	529	279
2009	74,157	3,333	6,218	2,885	1,511	508	580	286
2010	77,490
KENTUCKY
1990	4,000	821	1,102	281	120	82	62	18
1991	4,821	540	943	403	139	84	160	20
1992	5,361	271	722	451	148	92	188	22
1993	5,632	67	571	504	150	89	242	23
1994	5,699	813	1,206	393	159	46	164	24
1995	6,511	1,493	1,900	407	191	45	142	29
1996	8,004	1,483	1,892	409	231	57	86	34
1997	9,487	1,792	2,247	455	275	65	74	41
1998	11,280	3,166	3,755	589	345	120	73	51
1999	14,446	4,510	5,195	685	455	88	66	76
2000	18,956	6,391	7,160	769	495	131	70	73
2001	25,347	4,790	6,007	1,217	671	362	86	98
2002	30,137	3,641	4,891	1,250	794	259	82	116
2003	33,778	1,999	3,400	1,401	875	306	90	130
2004	35,777	1,048	2,415	1,367	903	223	103	138
2005	36,825	1,349	2,754	1,405	899	260	105	142
2006	38,174	2,896	4,282	1,386	906	214	119	147
2007	41,069	2,938	4,419	1,481	960	226	136	158
2008	44,008	2,005	3,574	1,569	1,012	235	152	170
2009	46,013	3,770	5,394	1,624	1,032	248	166	177
2010	49,782
LOUISIANA
1990	16,000	2,130	2,943	813	457	212	77	67
1991	18,130	1,517	2,398	881	497	179	130	74
1992	19,647	1,209	2,164	955	522	160	193	80
1993	20,856	831	2,018	1,187	539	153	411	84
1994	21,687	298	2,262	1,964	551	86	1,239	88
1995	21,986	499	2,607	2,108	555	98	1,365	90
1996	22,485	96	2,510	2,414	560	133	1,630	91
1997	22,581	92	2,829	2,737	562	118	1,965	92
1998	22,673	422	3,393	2,971	570	181	2,127	94
1999	23,094	1,136	3,802	2,666	588	188	1,787	104
2000	24,231	4,909	6,740	1,831	562	254	922	93
2001	29,140	3,740	5,896	2,156	703	392	949	112
2002	32,880	2,179	4,411	2,232	804	264	1,037	127
2003	35,059	1,367	3,746	2,379	853	262	1,129	135
2004	36,426	2,298	4,789	2,491	875	188	1,287	140
2005	38,724	4,298	6,880	2,582	925	189	1,318	149
2006	43,023	4,875	7,742	2,867	1,035	163	1,503	166
2007	47,898	4,481	7,793	3,312	1,159	261	1,708	185
2008	52,378	3,849	7,536	3,687	1,266	295	1,925	202
2009	56,228	1,580	5,593	4,013	1,351	332	2,113	217
2010	57,808
MAINE
1990	1,000	20	256	236	30	45	157	4
1991	1,020	(59)	134	193	28	45	116	4
1992	961	(18)	118	136	26	39	68	4
1993	943	0	119	119	25	31	60	4
1994	943	72	164	92	25	20	43	4
1995	1,015	79	164	85	27	18	36	4
1996	1,093	39	131	92	28	21	38	4
1997	1,132	41	175	134	29	20	79	5
1998	1,174	117	277	160	32	61	62	5
1999	1,291	167	338	171	36	65	64	6
2000	1,457	97	271	174	36	36	97	6
2001	1,554	12	277	265	39	77	144	6
2002	1,565	63	282	219	39	66	108	6
2003	1,628	128	368	240	40	76	117	6
2004	1,756	252	475	223	44	39	133	7
2005	2,008	189	440	251	51	54	138	8
2006	2,197	8	264	256	56	37	155	8
2007	2,205	(130)	153	283	55	42	178	8
2008	2,075	(156)	157	313	50	53	202	8
2009	1,919	(196)	121	317	44	45	220	7
2010	1,723
MARYLAND
1990	35,000	10,736	13,259	2,523	1,109	847	407	160
1991	45,736	7,101	9,756	2,655	1,350	720	390	195
1992	52,837	5,394	8,329	2,935	1,500	913	302	219
1993	58,232	5,437	8,542	3,105	1,620	936	309	241
1994	63,668	5,036	8,151	3,115	1,727	806	321	261
1995	68,704	3,768	6,976	3,208	1,805	863	263	278
1996	72,472	3,756	7,131	3,375	1,862	748	472	293
1997	76,228	6,315	10,069	3,754	1,963	789	689	313
1998	82,542	11,120	15,692	4,572	2,187	1,399	637	348
1999	93,663	14,478	19,493	5,015	2,532	1,526	521	436
2000	108,141	28,269	32,831	4,562	2,585	1,199	361	417
2001	136,410	20,352	26,973	6,621	3,362	2,324	410	525
2002	156,762	14,490	21,206	6,716	3,882	1,770	460	604
2003	171,252	12,591	20,034	7,443	4,196	2,086	501	660
2004	183,843	12,130	19,384	7,254	4,449	1,525	572	708
2005	195,973	9,130	16,437	7,307	4,677	1,291	585	755
2006	205,102	7,379	14,549	7,170	4,804	909	667	791
2007	212,481	4,259	12,299	8,040	4,866	1,597	758	819
2008	216,741	1,918	10,361	8,443	4,832	1,921	854	836
2009	218,658	4,656	13,063	8,407	4,735	1,891	938	844
2010	223,314
MASSACHUSETTS
1990	53,000	11,011	13,930	2,919	1,580	1,042	67	231
1991	64,011	7,277	10,725	3,448	1,814	881	486	267
1992	71,288	3,366	7,226	3,860	1,919	1,076	576	288
1993	74,654	2,018	5,959	3,941	1,938	1,285	418	299
1994	76,672	4,375	8,303	3,928	1,976	1,234	407	311
1995	81,047	7,290	11,296	4,006	2,098	1,091	483	334
1996	88,337	7,463	11,701	4,238	2,265	1,009	602	363
1997	95,799	7,926	12,340	4,414	2,434	872	714	393
1998	103,726	10,850	16,023	5,173	2,661	1,283	799	431
1999	114,576	14,175	19,778	5,603	2,978	1,397	711	518
2000	128,752	26,475	32,445	5,970	3,011	1,802	661	496
2001	155,227	17,058	26,599	9,541	3,734	4,604	605	598
2002	172,286	13,583	22,642	9,059	4,180	3,411	804	664
2003	185,869	8,870	18,569	9,699	4,493	3,612	877	716
2004	194,739	6,797	15,498	8,701	4,648	2,304	999	750
2005	201,536	6,285	14,953	8,668	4,715	2,154	1,022	777
2006	207,821	1,284	9,672	8,388	4,766	1,656	1,164	801
2007	209,106	(6,563)	3,001	9,564	4,662	2,771	1,324	806
2008	202,543	(5,439)	4,013	9,452	4,335	2,844	1,492	781
2009	197,103	274	9,824	9,550	4,061	3,088	1,640	761
2010	197,378
MICHIGAN
1990	23,000	6,877	8,403	1,526	724	594	104	105
1991	29,877	4,956	6,804	1,848	887	623	210	128
1992	34,833	3,800	5,868	2,068	996	659	268	145
1993	38,633	3,838	5,929	2,091	1,081	649	201	160
1994	42,471	5,759	7,669	1,910	1,191	361	179	178
1995	48,230	6,635	8,696	2,061	1,344	370	145	202
1996	54,865	5,719	8,164	2,445	1,491	485	241	227
1997	60,584	7,400	10,106	2,706	1,646	391	416	253
1998	67,984	10,636	14,131	3,495	1,882	1,003	320	289
1999	78,621	12,397	16,308	3,911	2,188	1,103	255	366
2000	91,015	10,744	14,970	4,226	2,235	1,200	440	351
2001	101,759	5,313	10,494	5,181	2,486	1,755	548	392
2002	107,072	(578)	4,218	4,796	2,573	1,168	643	413
2003	106,494	(3,786)	1,266	5,052	2,473	1,467	701	411
2004	102,708	(3,409)	1,038	4,447	2,284	967	800	396
2005	99,299	(2,730)	1,531	4,261	2,113	947	818	383
2006	96,569	(2,192)	1,966	4,158	1,976	877	932	373
2007	94,377	(3,166)	1,296	4,462	1,862	1,176	1,059	364
2008	91,212	(2,619)	1,814	4,433	1,723	1,164	1,193	352
2009	88,593	(516)	3,900	4,416	1,611	1,152	1,311	342
2010	88,077
MINNESOTA
1990	13,000	6,891	7,791	900	458	219	158	65
1991	19,891	5,699	6,947	1,248	643	155	360	90
1992	25,590	6,068	7,435	1,367	805	84	366	113
1993	31,658	5,786	7,632	1,846	966	130	613	136
1994	37,444	6,484	8,389	1,905	1,122	70	553	160
1995	43,928	7,599	9,732	2,133	1,303	107	535	188
1996	51,527	7,078	9,565	2,487	1,486	137	647	217
1997	58,605	6,744	9,836	3,092	1,654	108	1,085	245
1998	65,349	8,458	12,126	3,668	1,840	405	1,148	275
1999	73,808	10,270	14,256	3,986	2,074	573	1,000	339
2000	84,079	8,493	12,576	4,083	2,085	608	1,066	324
2001	92,572	5,532	10,437	4,905	2,266	1,036	1,246	357
2002	98,104	2,584	7,925	5,341	2,357	747	1,860	378
2003	100,688	951	6,640	5,689	2,358	916	2,026	388
2004	101,639	1,735	7,346	5,611	2,316	592	2,311	392
2005	103,374	1,925	7,535	5,610	2,299	548	2,364	399
2006	105,299	(461)	5,509	5,970	2,295	573	2,696	406
2007	104,837	(2,024)	4,365	6,389	2,225	695	3,065	405
2008	102,814	(2,070)	4,706	6,776	2,113	813	3,453	397
2009	100,744	(1,857)	5,195	7,052	2,011	861	3,792	389
2010	98,886
MISSISSIPPI
1990	3,000	723	871	148	91	40	4	13
1991	3,723	653	836	183	109	41	17	16
1992	4,376	591	805	214	125	36	34	18
1993	4,967	519	751	232	138	44	29	21
1994	5,487	605	851	246	151	26	47	23
1995	6,091	707	961	254	166	25	38	25
1996	6,798	542	849	307	179	36	64	28
1997	7,340	494	841	347	190	41	86	30
1998	7,834	1,126	1,498	372	209	58	73	33
1999	8,960	1,861	2,310	449	250	70	85	43
2000	10,821	912	1,418	506	262	95	107	42
2001	11,733	674	1,259	585	281	147	112	45
2002	12,407	880	1,390	510	293	91	78	48
2003	13,287	948	1,492	544	310	96	87	51
2004	14,234	1,496	2,055	559	330	80	95	55
2005	15,730	3,023	3,641	618	365	92	100	61
2006	18,753	3,871	4,587	716	446	85	113	72
2007	22,624	2,280	3,145	865	550	98	130	87
2008	24,904	804	1,774	970	600	131	144	96
2009	25,708	1,338	2,315	977	601	119	158	99
2010	27,045
MISSOURI
1990	8,000	1,406	1,928	522	236	189	63	35
1991	9,406	750	1,344	594	262	174	120	39
1992	10,156	299	945	646	270	183	152	41
1993	10,455	608	1,315	707	277	157	230	43
1994	11,063	2,115	2,729	614	311	76	179	48
1995	13,178	3,512	4,207	695	390	85	162	59
1996	16,689	3,539	4,483	944	490	142	239	73
1997	20,228	3,402	4,474	1,072	583	134	269	86
1998	23,630	4,363	5,849	1,486	690	245	449	102
1999	27,993	5,898	7,878	1,980	836	355	651	138
2000	33,893	9,959	12,357	2,398	868	344	1,056	130
2001	43,852	7,635	11,200	3,565	1,147	777	1,472	169
2002	51,487	5,281	9,251	3,970	1,349	576	1,847	198
2003	56,768	4,313	8,698	4,385	1,470	686	2,011	219
2004	61,080	4,624	9,070	4,446	1,555	363	2,293	235
2005	65,705	4,245	8,868	4,623	1,643	379	2,348	253
2006	69,950	2,184	7,181	4,997	1,717	332	2,678	269
2007	72,134	(927)	4,578	5,505	1,729	453	3,044	278
2008	71,208	(2,151)	3,716	5,867	1,649	516	3,428	274
2009	69,056	(1,247)	4,841	6,088	1,537	518	3,766	266
2010	67,809
MONTANA
1990	1,200	26	117	91	33	26	27	5
1991	1,226	7	94	87	32	19	31	5
1992	1,233	5	97	92	31	11	45	5
1993	1,238	(39)	66	105	30	12	58	5
1994	1,199	(14)	63	77	28	9	35	5
1995	1,185	(43)	51	94	26	9	54	5
1996	1,142	(29)	50	79	24	9	41	5
1997	1,113	(26)	40	66	23	8	30	4
1998	1,088	(46)	69	115	22	23	66	4
1999	1,042	(11)	108	119	21	27	67	4
2000	1,029	17	87	70	20	26	21	4
2001	1,046	(28)	84	112	20	48	40	4
2002	1,017	(24)	84	108	20	36	48	4
2003	993	(50)	76	126	20	50	52	4
2004	943	(31)	79	110	19	28	59	4
2005	912	(25)	91	116	19	33	61	4
2006	887	(37)	83	120	18	28	70	3
2007	851	(36)	102	138	18	36	81	3
2008	814	(47)	94	141	17	32	88	3
2009	767	(123)	28	151	16	36	96	3
2010	644
NEBRASKA
1990	5,500	2,284	2,601	317	183	69	39	26
1991	7,784	1,401	1,929	528	236	66	192	34
1992	9,185	1,281	1,824	543	270	72	163	39
1993	10,466	1,424	2,023	599	303	88	164	44
1994	11,890	1,847	2,469	622	344	69	159	51
1995	13,737	2,394	3,057	663	398	82	124	59
1996	16,131	2,486	3,296	810	462	144	135	68
1997	18,617	2,846	3,708	862	529	119	135	79
1998	21,463	3,629	4,642	1,013	614	167	141	92
1999	25,091	4,208	5,362	1,154	716	110	211	117
2000	29,300	3,232	4,520	1,288	732	204	239	113
2001	32,532	1,860	3,683	1,823	804	559	335	125
2002	34,392	109	2,137	2,028	836	392	667	132
2003	34,502	(560)	1,581	2,141	814	465	728	133
2004	33,942	1,172	3,148	1,976	775	242	828	131
2005	35,114	2,802	4,765	1,963	788	191	848	135
2006	37,917	2,192	4,316	2,124	851	160	967	146
2007	40,108	761	3,141	2,380	893	234	1,098	155
2008	40,869	(563)	2,005	2,568	892	282	1,237	158
2009	40,306	(2,039)	580	2,619	852	250	1,361	156
2010	38,268
NEVADA
1990	26,000	13,929	15,237	1,308	910	175	93	129
1991	39,929	9,639	11,435	1,796	1,249	168	204	176
1992	49,568	7,370	9,628	2,258	1,470	206	373	209
1993	56,937	7,483	10,032	2,549	1,648	228	435	238
1994	64,420	9,652	12,391	2,739	1,855	222	391	272
1995	74,072	10,552	13,719	3,167	2,105	344	407	312
1996	84,624	8,197	11,901	3,704	2,324	530	502	349
1997	92,820	6,747	10,914	4,167	2,476	664	648	378
1998	99,568	8,369	12,908	4,539	2,630	790	711	408
1999	107,937	10,210	15,244	5,034	2,837	935	787	475
2000	118,147	15,668	20,620	4,952	2,798	938	761	455
2001	133,815	11,183	17,396	6,213	3,176	1,734	787	516
2002	144,998	10,027	16,046	6,019	3,421	1,136	904	559
2003	155,025	9,519	16,020	6,501	3,616	1,304	983	598
2004	164,544	9,586	15,957	6,371	3,791	824	1,122	634
2005	174,130	9,399	15,974	6,575	3,958	797	1,148	671
2006	183,529	5,589	12,463	6,874	4,125	731	1,310	708
2007	189,118	(1,179)	6,500	7,679	4,177	1,283	1,489	729
2008	187,940	(4,000)	3,493	7,493	4,029	1,059	1,679	725
2009	183,940	(4,229)	3,524	7,753	3,803	1,397	1,843	710
2010	179,711
NEW HAMPSHIRE
1990	1,600	430	563	133	50	57	19	7
1991	2,030	278	431	153	60	61	24	9
1992	2,308	100	264	164	64	57	33	9
1993	2,409	(2)	141	143	63	32	38	10
1994	2,407	20	144	124	61	31	23	10
1995	2,427	35	155	120	60	40	11	10
1996	2,461	54	189	135	60	45	21	10
1997	2,515	89	223	134	60	36	27	10
1998	2,605	115	334	219	63	96	49	11
1999	2,720	289	547	258	69	97	79	13
2000	3,009	161	458	297	68	133	84	12
2001	3,170	(156)	334	490	73	317	88	12
2002	3,015	(224)	246	470	70	255	134	12
2003	2,790	(227)	230	457	64	239	143	11
2004	2,563	(159)	233	392	59	157	166	10
2005	2,404	(156)	232	388	55	153	170	9
2006	2,249	(41)	330	371	51	117	194	9
2007	2,208	(58)	381	439	50	159	221	9
2008	2,150	(209)	284	493	50	187	248	8
2009	1,941	(252)	251	503	44	178	273	7
2010	1,689
NEW JERSEY
1990	95,000	30,444	36,660	6,216	3,020	2,467	293	436
1991	125,444	19,300	26,079	6,779	3,695	2,277	274	533
1992	144,744	11,605	19,539	7,934	4,056	2,879	405	595
1993	156,348	10,726	19,157	8,431	4,270	3,023	499	639
1994	167,074	17,488	25,741	8,253	4,567	2,615	378	693
1995	184,562	21,074	30,477	9,403	5,033	3,235	366	769
1996	205,637	16,884	28,286	11,402	5,488	4,646	421	846
1997	222,520	19,246	30,167	10,921	5,877	3,408	721	915
1998	241,766	27,429	39,283	11,854	6,432	3,424	992	1,007
1999	269,195	33,840	46,326	12,486	7,193	3,036	1,041	1,217
2000	303,034	45,504	58,886	13,382	7,235	4,068	911	1,168
2001	348,538	22,638	45,219	22,581	8,387	11,675	1,175	1,343
2002	371,176	12,268	30,860	18,592	8,908	6,931	1,323	1,430
2003	383,443	2,893	21,815	18,922	9,043	6,960	1,441	1,478
2004	386,337	7,486	25,197	17,711	8,880	5,698	1,643	1,489
2005	393,823	15,513	32,861	17,348	8,854	5,293	1,682	1,519
2006	409,336	11,787	28,629	16,842	9,092	4,253	1,918	1,579
2007	421,123	513	19,013	18,500	9,203	5,493	2,180	1,624
2008	421,635	(4,393)	14,076	18,469	8,975	5,413	2,455	1,627
2009	417,242	(5,859)	13,384	19,243	8,612	6,321	2,699	1,610
2010	411,383
NEW MEXICO
1990	20,000	2,327	3,321	994	565	112	233	83
1991	22,327	1,942	3,140	1,198	613	128	365	92
1992	24,270	1,887	3,272	1,385	654	174	458	100
1993	26,157	1,610	3,163	1,553	688	186	572	107
1994	27,766	2,062	3,479	1,417	720	160	422	114
1995	29,829	2,973	4,426	1,453	775	218	336	123
1996	32,802	2,326	4,024	1,698	835	411	318	134
1997	35,128	1,892	3,574	1,682	874	163	503	142
1998	37,020	3,085	4,787	1,702	924	222	405	152
1999	40,105	4,404	6,321	1,917	1,014	232	492	179
2000	44,508	6,086	8,388	2,302	1,024	401	706	172
2001	50,594	6,432	9,195	2,763	1,184	968	417	195
2002	57,025	6,985	9,234	2,249	1,353	425	251	220
2003	64,011	5,996	8,563	2,567	1,525	522	273	247
2004	70,007	4,764	7,308	2,544	1,660	301	313	270
2005	74,771	2,698	5,351	2,653	1,749	297	319	288
2006	77,469	948	3,612	2,664	1,775	227	364	299
2007	78,416	1,144	3,903	2,759	1,749	295	413	302
2008	79,560	2,485	5,348	2,863	1,731	360	465	307
2009	82,045	2,050	5,024	2,974	1,755	392	511	317
2010	84,095
NEW YORK
1990	358,000	51,054	73,588	22,534	10,340	7,953	2,721	1,520
1991	409,054	29,180	51,546	22,366	11,220	7,337	2,134	1,674
1992	438,234	13,412	38,076	24,664	11,519	8,733	2,652	1,761
1993	451,645	13,798	38,287	24,489	11,565	8,980	2,131	1,814
1994	465,443	31,643	55,664	24,021	11,914	8,436	1,770	1,901
1995	497,086	42,604	66,843	24,239	12,713	7,258	2,225	2,044
1996	539,690	30,499	58,179	27,680	13,499	9,347	2,642	2,192
1997	570,189	25,042	54,056	29,014	13,980	8,755	3,977	2,302
1998	595,231	34,523	64,212	29,689	14,518	9,320	3,433	2,418
1999	629,754	44,590	73,732	29,142	15,329	7,749	3,350	2,714
2000	674,345	72,122	101,063	28,941	15,126	7,773	3,442	2,600
2001	746,467	35,193	75,565	40,372	16,946	16,587	3,960	2,878
2002	781,660	15,596	53,859	38,263	17,714	12,718	4,818	3,014
2003	797,256	2,148	42,015	39,867	17,821	13,723	5,248	3,075
2004	799,405	(946)	35,080	36,026	17,503	9,458	5,981	3,084
2005	798,459	(5,717)	30,412	36,129	17,060	9,863	6,125	3,081
2006	792,742	(10,270)	25,055	35,325	16,549	8,735	6,982	3,059
2007	782,472	(17,945)	22,371	40,316	15,950	13,405	7,940	3,021
2008	764,527	(24,223)	18,098	42,321	15,205	15,223	8,942	2,952
2009	740,304	(35,369)	7,806	43,175	14,336	16,156	9,824	2,859
2010	704,935
NORTH CAROLINA
1990	25,000	15,377	16,679	1,302	908	235	30	128
1991	40,377	12,090	13,801	1,711	1,307	179	43	182
1992	52,467	11,129	13,170	2,041	1,620	148	46	227
1993	63,596	12,352	14,764	2,412	1,926	118	95	273
1994	75,948	17,148	19,958	2,810	2,315	78	86	331
1995	93,097	21,702	25,190	3,488	2,838	150	93	407
1996	114,799	21,717	25,897	4,180	3,409	153	126	492
1997	136,516	22,925	27,889	4,964	3,978	146	261	579
1998	159,441	28,509	34,659	6,150	4,638	509	322	680
1999	187,950	33,538	40,627	7,089	5,439	488	281	881
2000	221,487	24,090	31,565	7,475	5,593	621	408	853
2001	245,577	17,209	26,501	9,292	6,093	1,967	286	946
2002	262,786	14,270	23,348	9,078	6,387	1,378	300	1,012
2003	277,056	14,364	23,567	9,203	6,578	1,231	327	1,068
2004	291,420	19,037	28,222	9,185	6,762	927	372	1,123
2005	310,457	20,358	29,937	9,579	7,080	921	381	1,197
2006	330,815	15,537	25,378	9,841	7,440	689	436	1,276
2007	346,352	11,722	22,356	10,634	7,646	1,159	493	1,336
2008	358,075	7,641	18,716	11,075	7,734	1,402	557	1,381
2009	365,715	5,103	16,268	11,165	7,706	1,436	612	1,411
2010	370,819
NORTH DAKOTA
1990	500	34	82	48	14	25	7	2
1991	534	27	75	48	15	21	10	2
1992	561	21	71	50	15	25	8	2
1993	582	(33)	36	69	15	17	35	2
1994	549	0	44	44	14	7	22	2
1995	548	(6)	41	47	13	6	25	2
1996	542	(25)	41	66	13	7	44	2
1997	517	(25)	19	44	11	7	24	2
1998	492	(10)	45	55	11	31	11	2
1999	483	32	89	57	11	34	10	2
2000	514	12	51	39	11	10	16	2
2001	526	2	54	52	11	26	13	2
2002	527	(13)	33	46	12	23	10	2
2003	514	(26)	21	47	11	22	11	2
2004	489	(18)	21	39	10	16	11	2
2005	471	(21)	20	41	10	15	14	2
2006	450	(18)	21	39	9	13	15	2
2007	432	(23)	23	46	9	19	16	2
2008	409	(4)	48	52	8	23	19	2
2009	405	23	80	57	8	27	20	2
2010	429
OHIO
1990	11,000	3,159	3,866	707	344	294	20	50
1991	14,159	2,449	3,142	693	419	183	31	61
1992	16,608	1,746	2,582	836	470	128	170	69
1993	18,353	1,580	2,566	986	507	229	174	76
1994	19,934	2,566	3,433	867	552	94	137	83
1995	22,500	3,606	4,590	984	630	155	104	95
1996	26,106	4,645	5,839	1,194	739	173	171	112
1997	30,751	6,070	7,632	1,562	885	129	415	133
1998	36,821	7,808	9,864	2,056	1,078	458	360	161
1999	44,628	9,558	11,937	2,379	1,318	557	285	218
2000	54,187	12,955	15,575	2,620	1,379	707	325	209
2001	67,142	8,511	12,642	4,131	1,727	1,589	557	258
2002	75,653	5,669	9,775	4,106	1,938	1,103	774	291
2003	81,322	2,408	6,764	4,356	2,050	1,150	843	313
2004	83,730	3,378	7,485	4,107	2,059	765	961	323
2005	87,108	7,038	11,197	4,159	2,093	748	983	336
2006	94,145	5,755	10,315	4,560	2,238	837	1,122	363
2007	99,900	1,073	5,982	4,909	2,338	911	1,275	385
2008	100,973	(1,369)	3,733	5,102	2,292	984	1,437	389
2009	99,605	(1,407)	3,728	5,135	2,176	996	1,579	384
2010	98,198
OKLAHOMA
1990	15,000	2,564	3,307	743	437	126	116	64
1991	17,564	2,035	2,968	933	495	128	237	73
1992	19,599	2,285	3,262	977	545	137	213	82
1993	21,885	2,509	3,547	1,038	601	174	172	91
1994	24,394	3,303	4,471	1,168	673	116	277	103
1995	27,696	3,964	5,214	1,250	763	202	169	117
1996	31,660	3,440	4,793	1,353	852	223	147	131
1997	35,100	3,727	5,246	1,519	936	150	288	145
1998	38,827	5,549	7,427	1,878	1,053	235	426	164
1999	44,376	6,757	9,089	2,332	1,216	324	586	206
2000	51,132	7,743	10,271	2,528	1,242	360	729	197
2001	58,875	5,658	8,520	2,862	1,439	563	634	227
2002	64,533	3,580	6,300	2,720	1,566	478	428	249
2003	68,113	2,823	5,637	2,814	1,622	464	466	262
2004	70,935	4,487	7,260	2,773	1,654	313	532	273
2005	75,422	4,814	7,710	2,896	1,735	327	543	291
2006	80,237	3,715	6,771	3,056	1,827	299	621	309
2007	83,951	3,837	7,126	3,289	1,883	377	705	324
2008	87,789	3,947	7,473	3,526	1,941	452	795	339
2009	91,736	2,473	6,178	3,705	2,001	477	873	354
2010	94,209
OREGON
1990	25,500	7,693	8,931	1,238	796	215	112	115
1991	33,193	6,799	8,659	1,860	1,001	209	506	144
1992	39,992	6,815	8,930	2,115	1,180	219	545	171
1993	46,807	5,800	8,786	2,986	1,346	298	1,145	197
1994	52,607	6,437	9,401	2,964	1,490	271	983	221
1995	59,043	7,996	10,690	2,694	1,658	268	520	248
1996	67,039	7,075	10,350	3,275	1,839	461	697	278
1997	74,114	6,487	10,399	3,912	1,994	516	1,097	305
1998	80,601	8,543	12,687	4,144	2,164	574	1,071	335
1999	89,145	10,642	14,691	4,049	2,389	452	809	400
2000	99,788	12,124	16,063	3,939	2,396	611	547	385
2001	111,912	8,098	13,235	5,137	2,678	1,214	813	431
2002	120,010	3,738	9,660	5,922	2,836	1,106	1,517	463
2003	123,748	1,878	7,995	6,117	2,863	1,126	1,651	477
2004	125,626	4,398	10,174	5,776	2,836	572	1,884	484
2005	130,024	5,630	11,505	5,875	2,885	560	1,928	501
2006	135,655	1,804	7,997	6,193	2,976	495	2,199	523
2007	137,458	(1,106)	5,503	6,609	2,952	628	2,499	530
2008	136,352	(2,363)	4,485	6,848	2,844	662	2,816	526
2009	133,989	(3,358)	3,650	7,008	2,707	692	3,091	517
2010	130,632
PENNSYLVANIA
1990	25,000	4,778	6,637	1,859	746	689	315	109
1991	29,778	3,735	5,768	2,033	857	665	385	126
1992	33,513	2,399	4,340	1,941	923	524	357	137
1993	35,912	1,822	3,711	1,889	956	472	316	145
1994	37,734	3,858	5,743	1,885	1,013	349	367	156
1995	41,592	5,978	8,103	2,125	1,136	443	369	176
1996	47,570	5,722	8,246	2,524	1,286	459	580	199
1997	53,292	6,134	9,282	3,148	1,437	366	1,122	223
1998	59,425	7,517	11,599	4,082	1,618	860	1,352	251
1999	66,943	8,351	12,714	4,363	1,824	1,377	855	307
2000	75,292	23,442	27,394	3,952	1,833	1,079	750	290
2001	98,734	16,928	23,434	6,506	2,494	2,529	1,103	380
2002	115,662	12,201	18,792	6,591	2,950	1,739	1,457	445
2003	127,862	7,237	14,561	7,324	3,236	2,010	1,586	492
2004	135,099	5,990	12,948	6,958	3,358	1,271	1,809	520
2005	141,089	5,228	12,540	7,312	3,427	1,489	1,852	544
2006	146,317	2,990	10,615	7,625	3,477	1,472	2,112	564
2007	149,307	240	8,471	8,231	3,461	1,795	2,400	576
2008	149,547	(1,376)	7,131	8,507	3,365	1,861	2,704	577
2009	148,171	(436)	8,300	8,736	3,232	1,962	2,971	572
2010	147,735
RHODE ISLAND
1990	8,500	2,015	2,491	476	258	165	16	38
1991	10,515	1,526	2,141	615	305	125	140	45
1992	12,041	1,308	2,146	838	342	162	283	50
1993	13,349	1,210	2,083	873	372	182	264	55
1994	14,559	1,433	2,283	850	401	173	216	60
1995	15,992	1,454	2,342	888	434	188	200	66
1996	17,446	838	1,790	952	457	226	198	71
1997	18,284	847	1,733	886	468	205	139	74
1998	19,131	1,451	2,258	807	488	176	65	78
1999	20,582	1,855	2,791	936	525	192	128	90
2000	22,436	3,498	4,525	1,027	520	215	205	86
2001	25,934	2,073	3,410	1,337	611	452	173	100
2002	28,007	709	2,101	1,392	658	395	231	108
2003	28,716	280	1,784	1,504	662	481	251	111
2004	28,996	(5)	1,341	1,346	654	293	287	112
2005	28,991	(342)	979	1,321	637	277	295	112
2006	28,648	(417)	856	1,273	613	214	335	111
2007	28,232	(809)	592	1,401	589	324	380	109
2008	27,423	(164)	1,282	1,446	554	357	429	106
2009	27,258	1,108	2,645	1,537	542	420	470	105
2010	28,366
SOUTH CAROLINA
1990	6,000	2,323	2,669	346	196	106	16	28
1991	8,323	2,037	2,445	408	258	90	24	37
1992	10,359	1,732	2,170	438	307	75	12	44
1993	12,091	1,491	1,990	499	346	58	44	50
1994	13,583	2,074	2,600	526	389	43	37	57
1995	15,656	3,038	3,659	621	455	59	39	67
1996	18,695	3,353	4,073	720	539	67	34	80
1997	22,048	3,770	4,640	870	631	87	58	94
1998	25,819	5,749	6,898	1,149	760	171	105	113
1999	31,568	8,152	9,478	1,326	953	167	48	158
2000	39,721	8,550	9,992	1,442	1,016	194	79	153
2001	48,271	6,706	8,545	1,839	1,236	322	95	186
2002	54,977	7,931	9,850	1,919	1,393	261	53	212
2003	62,909	10,050	12,128	2,078	1,582	196	58	242
2004	72,959	9,614	11,961	2,347	1,826	177	63	281
2005	82,573	8,077	10,757	2,680	2,046	247	69	318
2006	90,650	6,493	9,302	2,809	2,211	171	78	349
2007	97,143	4,336	7,446	3,110	2,322	327	87	374
2008	101,479	2,211	5,388	3,177	2,362	324	100	391
2009	103,690	696	3,904	3,208	2,334	366	107	400
2010	104,386
SOUTH DAKOTA
1990	700	99	145	46	20	16	7	3
1991	799	37	85	48	22	16	7	3
1992	836	0	53	53	22	20	8	3
1993	836	(14)	54	68	21	15	28	3
1994	823	18	65	47	20	7	17	3
1995	841	(2)	63	65	20	6	35	3
1996	839	(37)	39	76	19	11	43	3
1997	802	8	67	59	18	11	27	3
1998	809	56	115	59	19	24	13	3
1999	866	32	124	92	20	29	39	4
2000	897	91	165	74	19	27	24	3
2001	988	41	130	89	22	42	22	4
2002	1,029	6	109	103	23	44	31	4
2003	1,035	(17)	84	101	24	41	32	4
2004	1,019	(32)	61	93	23	28	38	4
2005	986	(44)	56	100	22	34	40	4
2006	942	(18)	84	102	21	35	43	4
2007	924	42	149	107	20	32	51	4
2008	966	32	158	126	21	42	59	4
2009	997	(63)	69	132	22	43	62	4
2010	935
TENNESSEE
1990	9,500	3,402	3,915	513	306	132	31	44
1991	12,902	2,955	3,552	597	395	128	18	56
1992	15,856	2,900	3,631	731	473	153	37	68
1993	18,756	3,090	3,987	897	551	211	55	80
1994	21,847	4,208	5,131	923	645	139	45	94
1995	26,055	5,108	6,161	1,053	768	128	45	112
1996	31,163	4,880	6,141	1,261	896	188	45	132
1997	36,042	5,148	6,646	1,498	1,022	198	126	152
1998	41,191	7,709	9,527	1,818	1,189	247	205	177
1999	48,900	10,721	12,738	2,017	1,437	203	139	238
2000	59,623	13,181	15,488	2,307	1,508	304	265	230
2001	72,804	10,406	13,451	3,045	1,851	689	225	280
2002	83,211	8,982	12,343	3,361	2,099	482	460	320
2003	92,192	9,711	13,257	3,546	2,293	397	501	355
2004	101,904	10,235	14,081	3,846	2,500	383	571	393
2005	112,139	8,035	12,258	4,223	2,716	490	585	432
2006	120,174	6,258	10,778	4,520	2,860	529	668	463
2007	126,432	6,481	11,297	4,816	2,948	623	758	487
2008	132,913	3,920	8,909	4,989	3,038	584	854	512
2009	136,833	(809)	4,315	5,124	3,046	613	938	528
2010	136,023
TEXAS
1990	440,000	70,896	90,007	19,111	12,702	2,556	1,986	1,867
1991	510,896	53,905	75,077	21,172	14,174	2,585	2,302	2,111
1992	564,801	47,168	73,078	25,910	15,266	3,440	4,889	2,315
1993	611,969	51,396	79,326	27,930	16,267	3,689	5,464	2,510
1994	663,365	71,868	100,586	28,718	17,617	2,836	5,515	2,749
1995	735,234	87,397	118,866	31,469	19,504	3,634	5,269	3,061
1996	822,631	71,809	109,269	37,460	21,360	5,870	6,850	3,380
1997	894,440	62,825	104,249	41,424	22,767	4,221	10,789	3,647
1998	957,265	77,654	122,298	44,644	24,221	4,459	12,039	3,925
1999	1,034,919	92,240	139,531	47,291	26,085	4,706	11,970	4,529
2000	1,127,161	132,157	181,723	49,566	25,932	6,653	12,636	4,345
2001	1,259,318	90,194	153,519	63,325	29,208	15,465	13,797	4,854
2002	1,349,512	61,306	122,199	60,893	31,198	10,019	14,474	5,202
2003	1,410,818	41,157	105,088	63,931	32,179	10,549	15,764	5,439
2004	1,451,976	52,765	117,707	64,942	32,506	8,865	17,971	5,599
2005	1,504,741	64,793	130,127	65,334	33,185	7,948	18,398	5,804
2006	1,569,533	46,639	113,392	66,753	34,283	5,436	20,980	6,054
2007	1,616,172	19,225	91,513	72,288	34,830	7,374	23,849	6,235
2008	1,635,397	(3,467)	72,869	76,336	34,565	8,596	26,864	6,311
2009	1,631,930	(23,560)	55,048	78,608	33,675	9,126	29,508	6,299
2010	1,608,371
UTAH
1990	15,000	4,353	5,045	692	465	115	45	67
1991	19,353	3,124	4,100	976	567	110	217	82
1992	22,476	2,914	3,943	1,029	640	119	175	94
1993	25,390	3,621	4,843	1,222	721	158	236	107
1994	29,011	5,569	6,765	1,196	838	105	128	125
1995	34,580	6,561	7,958	1,397	998	138	113	148
1996	41,141	6,037	7,737	1,700	1,160	248	119	173
1997	47,178	5,953	7,805	1,852	1,305	176	174	197
1998	53,131	7,648	9,877	2,229	1,473	294	238	224
1999	60,780	10,114	12,603	2,489	1,700	388	119	283
2000	70,892	8,023	10,587	2,564	1,748	356	187	273
2001	78,915	6,151	9,415	3,264	1,927	776	257	304
2002	85,066	5,533	9,021	3,488	2,049	502	609	328
2003	90,599	3,543	7,289	3,746	2,146	588	663	349
2004	94,142	2,691	6,325	3,634	2,178	337	756	363
2005	96,833	3,589	7,235	3,646	2,182	316	775	373
2006	100,422	3,371	7,124	3,753	2,219	265	882	387
2007	103,793	1,071	5,190	4,119	2,252	463	1,003	400
2008	104,865	(1,740)	2,558	4,298	2,217	546	1,130	405
2009	103,125	(2,662)	1,661	4,323	2,099	584	1,243	398
2010	100,463
VERMONT
1990	600	30	226	196	19	31	143	3
1991	630	(50)	131	181	18	35	125	3
1992	580	(27)	87	114	16	36	60	2
1993	553	(29)	47	76	14	35	25	2
1994	524	(16)	57	73	13	29	28	2
1995	508	(6)	56	62	13	24	24	2
1996	502	(21)	53	74	12	28	31	2
1997	482	(28)	41	69	11	21	34	2
1998	454	(51)	42	93	11	46	34	2
1999	403	(25)	50	75	9	37	26	2
2000	377	2	62	60	8	40	11	1
2001	379	(49)	57	106	9	85	11	1
2002	330	(7)	66	73	8	53	11	1
2003	323	(17)	74	91	8	70	12	1
2004	306	22	82	60	8	38	13	1
2005	328	10	69	59	9	35	14	1
2006	338	(3)	51	54	9	28	16	1
2007	334	(2)	67	69	9	41	17	1
2008	332	(42)	67	109	9	39	60	1
2009	290	(94)	23	117	8	43	64	1
2010	196
VIRGINIA
1990	49,000	10,296	13,072	2,776	1,464	840	259	214
1991	59,296	7,187	10,134	2,947	1,685	844	171	248
1992	66,483	5,311	8,565	3,254	1,821	935	225	272
1993	71,794	5,149	8,512	3,363	1,920	932	219	293
1994	76,943	6,736	10,215	3,479	2,040	813	310	316
1995	83,679	7,176	11,323	4,147	2,196	1,229	378	344
1996	90,855	7,148	11,822	4,674	2,355	1,498	448	373
1997	98,003	10,508	15,406	4,898	2,561	1,212	717	407
1998	108,511	15,871	21,387	5,516	2,903	1,518	636	459
1999	124,382	19,741	25,509	5,768	3,373	1,351	466	578
2000	144,124	39,731	45,969	6,238	3,466	1,844	372	555
2001	183,855	27,070	36,901	9,831	4,572	4,294	257	708
2002	210,925	16,905	26,133	9,228	5,275	2,805	336	812
2003	227,830	8,976	19,079	10,103	5,621	3,238	366	878
2004	236,806	8,324	17,052	8,728	5,716	1,684	416	912
2005	245,130	8,062	16,956	8,894	5,773	1,748	428	945
2006	253,193	8,909	17,941	9,032	5,827	1,744	486	976
2007	262,101	7,149	17,057	9,908	5,904	2,441	553	1,011
2008	269,250	1,019	11,577	10,558	5,928	2,967	625	1,039
2009	270,269	(2,819)	7,485	10,304	5,774	2,802	686	1,043
2010	267,450
WASHINGTON
1990	39,000	15,924	18,023	2,099	1,288	573	54	185
1991	54,924	13,370	15,996	2,626	1,704	560	121	242
1992	68,293	11,380	14,450	3,070	2,030	592	158	291
1993	79,673	9,742	13,437	3,695	2,289	722	352	332
1994	89,415	10,676	14,747	4,071	2,526	657	515	373
1995	100,091	11,082	15,726	4,644	2,779	910	539	416
1996	111,173	9,285	14,291	5,006	2,999	815	737	456
1997	120,458	10,006	15,406	5,400	3,196	870	840	494
1998	130,464	12,302	18,830	6,528	3,449	1,602	939	539
1999	142,766	13,378	20,278	6,900	3,742	1,357	1,173	629
2000	156,144	27,479	34,162	6,683	3,692	1,414	975	602
2001	183,623	18,086	27,167	9,081	4,398	2,670	1,306	708
2002	201,709	11,133	20,113	8,980	4,811	1,972	1,419	777
2003	212,842	7,719	17,584	9,865	4,997	2,502	1,546	820
2004	220,560	11,609	20,608	8,999	5,082	1,303	1,763	850
2005	232,170	12,296	21,550	9,254	5,277	1,278	1,804	895
2006	244,466	8,107	17,909	9,802	5,495	1,306	2,058	943
2007	252,573	5,362	16,094	10,732	5,583	1,835	2,339	974
2008	257,935	2,985	14,178	11,193	5,592	1,972	2,633	995
2009	260,921	505	12,120	11,615	5,539	2,176	2,893	1,007
2010	261,426
WEST VIRGINIA
1990	1,200	(17)	100	117	32	34	46	5
1991	1,183	(24)	50	74	30	27	13	5
1992	1,158	(53)	43	96	28	24	39	5
1993	1,105	(13)	53	66	26	13	23	4
1994	1,092	(26)	41	67	25	12	25	4
1995	1,067	(19)	49	68	23	10	30	4
1996	1,048	(4)	46	50	22	6	18	4
1997	1,044	(61)	45	106	21	5	75	4
1998	983	(11)	65	76	20	22	30	4
1999	972	18	96	78	19	39	16	4
2000	989	10	97	87	19	32	32	4
2001	999	(86)	62	148	20	83	42	4
2002	913	(40)	41	81	18	53	6	4
2003	873	(31)	50	81	17	54	6	3
2004	842	0	76	76	17	49	6	3
2005	843	7	73	66	17	36	9	3
2006	850	(12)	58	70	18	39	9	3
2007	838	(17)	57	74	18	44	9	3
2008	822	(23)	55	78	17	45	12	3
2009	799	(18)	65	83	17	52	12	3
2010	781
WISCONSIN
1990	9,500	3,372	3,798	426	304	27	51	44
1991	12,872	3,282	3,838	556	398	18	83	57
1992	16,154	3,148	3,831	683	484	22	107	70
1993	19,302	3,138	3,954	816	565	78	91	82
1994	22,440	4,156	5,059	903	659	46	102	96
1995	26,596	5,228	6,286	1,058	782	91	71	114
1996	31,824	5,069	6,269	1,200	913	63	89	135
1997	36,893	4,920	6,299	1,379	1,035	70	120	154
1998	41,813	6,232	7,900	1,668	1,173	223	96	176
1999	48,045	7,885	9,789	1,904	1,353	235	93	223
2000	55,930	6,798	8,903	2,105	1,388	379	123	215
2001	62,728	3,661	6,953	3,292	1,541	1,372	137	242
2002	66,389	1,467	4,096	2,629	1,605	577	192	256
2003	67,856	1,013	3,700	2,687	1,593	622	210	262
2004	68,869	2,493	5,083	2,590	1,569	518	238	266
2005	71,362	4,560	7,189	2,629	1,591	519	244	275
2006	75,921	6,240	8,897	2,657	1,679	406	279	293
2007	82,162	3,350	6,320	2,970	1,817	520	316	317
2008	85,512	(1,041)	2,065	3,106	1,862	559	355	330
2009	84,471	(2,599)	454	3,053	1,771	566	391	326
2010	81,872
WYOMING
1990	1,500	105	164	59	41	12	−	6
1991	1,605	82	155	73	42	13	11	6
1992	1,687	3	87	84	42	14	21	7
1993	1,691	(11)	83	94	41	16	30	7
1994	1,680	6	91	85	39	12	27	7
1995	1,685	13	112	99	39	18	35	7
1996	1,698	0	96	96	38	19	32	7
1997	1,699	5	89	84	37	15	25	7
1998	1,704	47	123	76	36	21	12	7
1999	1,751	59	153	94	37	32	18	7
2000	1,810	161	256	95	37	22	29	7
2001	1,971	155	267	112	41	49	15	8
2002	2,126	164	267	103	46	31	18	8
2003	2,289	87	210	123	50	46	18	9
2004	2,376	33	142	109	52	25	22	9
2005	2,409	114	220	106	53	21	24	9
2006	2,523	220	330	110	55	19	26	10
2007	2,743	217	355	138	61	37	30	11
2008	2,959	200	348	148	66	36	34	11
2009	3,159	181	341	160	71	41	36	12
2010	3,340

Note : See text for a description of how estimates were constructed. Negative numbers in parentheses

Fourth, both the Pew and OIS estimates go back in time only to 2000 (and OIS has not published estimates for 2001–2004). As we describe below, it is possible to use parallel methods to produce annual estimates back to 1990. This longer time horizon for estimates at the national and state levels is useful for policy analysts and researchers who are interested in understanding the correlates of change in the size of the unauthorized immigrant population.

Below we describe an extension of the residual method that produces separate estimates of arrivals and departures of unauthorized immigrants in addition to estimates of the size of the unauthorized immigrant population. Compared to Pew and OIS, our estimates are more statistically reliable, are available annually at both the state and national levels for 1990 to 2010, and include information at the national and state levels about both the size of the population and the components of annual inflows into and outflows from the population.

Research Design

Our estimates are based on a comparison of the total foreign-born population to the legally resident foreign-born population; the difference between them is taken to represent the unauthorized foreign-born population. Detailed estimates were derived for each state, annually, from 1990 to 2010, and the results were summed to produce national estimates. In this section, we describe the data that we use to account for each element of both the total foreign-born and the legally resident foreign-born populations; in Appendix Table A1 we summarize these several data elements. We then describe our techniques for deriving annual national and state estimates of the unauthorized immigrant population and of the components of annual inflows into and outflows from that population.

Table A1

Sources and Descriptions of Data Used to Construct Estimates

Type of data		Source	Description and Notes
Lawful Resident Population
1	Legal Permanent Residents (LPRs)	Department of Homeland Security	Data for each State, by year of entry, for new arrivals and adjustments of status
2	Nonimmigrant Resident Population¹	Department of Homeland Security	Based on arrival and departure statistics, by length of stay, for each State
3	Refugees Admitted	Office of Refugee Resettlement, Department of Health and Human Services	Annual admissions for each State, by year of entry
Total Foreign-Born Population
4	Moved to the U.S. Each Year, 1990 to 1999	2000 U.S. Decennial Census (from IPUMS.org)	Data for each State, by year of entry, collected in the 2000 Census
5	Moved to the U.S. Each Year, 2000 to 2009	American Community Surveys (from IPUMS.org)	Data for each State, by year of entry, collected by the Census Bureau in the American Community Survey
Other data
6	Emigration Rates¹	U.S. Bureau of the Census, Technical Report # 9²	Emigration rate for 10-year period extrapolated to single years; assumes U.S. rates apply to each State
7	Undercount Rates¹	See Text.	Assumes U.S. rates apply to each State
8	Removals of Unauthorized Residents	Department of Homeland Security	Statistics for each State, by year of entry, resided in the U.S. for 6 months or more
9	Adjustments from Unauthorized to Lawful Status	Department of Homeland Security	Estimates for each State, by year of entry, based on number of years between entry and adjustment of status
10	Mortality Rates¹	Age-Standardized Crude Death Rates³	Assumes U.S. rates apply to each State

¹The effects of alternative assumptions for selected variables – mortality rates, emigration rates, and undercount rates – on the size of the estimated total unauthorized resident population are discussed below in the section “Effects of alternative assumptions.” See, especially, Table 4.

²Ahmed and Robinson (1994)

³Rate for unauthorized immigrants (3.9/1000) based on IRCA distribution by age and Hispanic mortality rates for 1990; rate for legal residents (5.7/1000) based on legal immigrants by age in 1994 and Hispanic mortality rates for 1990.

Data

Estimates of the total foreign-born population—separately by state and by year of entry into the country—were obtained from the 2000 decennial census (for those moving to the U.S. between 1990 and 1999) and from the 2010 ACS (for those moving to the U.S. between 2000 and 2009). Estimates of the legally resident foreign-born population combine counts of (1) legal permanent residents for each state, by year of entry, and for both new arrivals and those who adjust their status (obtained from the DHS); (2) nonimmigrant residents^⁴ for each state and by length of stay (based on arrival and departure statistics obtained from DHS); and (3) refugees for each state and by year of entry (obtained from the Office of Refugee Resettlement).

Our method also requires estimates and assumptions about (1) emigration rates (discussed below); (2) Census and ACS undercount rates (discussed below); (3) removals of unauthorized residents for each state and by year of entry among those living in the U.S. for 6 months or longer (which we base on data obtained from DHS); (4) adjustments from unauthorized to lawful status by state, year of entry, and year of adjustment (also based on data obtained from DHS); and (5) mortality rates (which we base on age-standardized crude death rates for relevant populations as discussed below). In the next few paragraphs we explain and justify our estimates and assumptions for mortality rates, undercount rates, and emigration rates. Later, we explore the consequences of alternative assumptions about these three sets of rates for our estimates of the size of the unauthorized immigrant population.

Mortality Rates

To estimate the annual number of deaths, we computed age-adjusted crude death rates separately for unauthorized and legal immigrants. In both calculations, we used age-specific survival rates for Hispanic males in 1990 (Ahmed and Robinson 1994: Table A-2). To compute the rate for unauthorized immigrants, we used the age distribution of applicants under IRCA; for legal immigrants, we used the age distribution of legal immigrants in 1994. The crude death rate was estimated to be 3.9 per 1,000 for unauthorized immigrants and 5.7 per 1,000 for legal immigrants. We assume that national rates apply to each state. Note that mortality is a very small component of change in our estimates. As described below, varying the rates by 25 percent would change the estimated total population by about ±85,000, or less than one percent. The effects of increasing or decreasing mortality rates for both authorized and unauthorized immigrants would be offsetting.

Table A2

Standard Errors for ACS Estimates of the Number of Foreign-born People Entering Between 2000 and 2009, by State

	Est.	Stand. Error (SE)	SE as % of Estimate		Est.	Stand. Error (SE)	SE as % of Estimate

	(1)	(2)	(3)=(2)/(1)		(1)	(2)	(3)=(2)/(1)
U.S. Total	13,161	71	0.54%	Missouri	103	6	5.85%
Alabama	94	6	6.12%	Montana	6	1	22.37%
Alaska	15	2	12.90%	Nebraska	40	3	8.34%
Arizona	258	10	3.84%	Nevada	155	8	4.91%
Arkansas	63	4	7.08%	New Hampshire	20	3	13.24%
California	2,691	31	1.17%	New Jersey	603	15	2.47%
Colorado	183	8	4.57%	New Mexico	71	5	7.36%
Connecticut	170	8	4.71%	New York	1,265	22	1.71%
Delaware	27	3	11.94%	North Carolina	317	11	3.47%
D.C.	34	3	9.92%	North Dakota	4	1	22.55%
Florida	1,233	21	1.73%	Ohio	183	8	4.39%
Georgia	395	12	3.10%	Oklahoma	93	5	5.81%
Hawaii	70	5	7.34%	Oregon	125	7	5.54%
Idaho	33	3	10.30%	Pennsylvania	282	10	3.70%
Illinois	555	14	2.61%	Rhode Island	41	4	9.64%
Indiana	135	7	5.10%	South Carolina	104	6	6.11%
Iowa	60	4	6.87%	South Dakota	9	2	18.68%
Kansas	68	5	6.77%	Tennessee	143	7	5.19%
Kentucky	70	5	7.46%	Texas	1,429	23	1.62%
Louisiana	73	5	7.28%	Utah	85	6	6.73%
Maine	15	2	14.76%	Vermont	9	1	14.21%
Maryland	314	11	3.45%	Virginia	360	12	3.24%
Massachusetts	350	11	3.27%	Washington	315	11	3.46%
Michigan	203	8	3.93%	West Virginia	8	2	19.80%
Minnesota	149	7	4.58%	Wisconsin	97	5	5.38%
Mississippi	29	3	11.60%	Wyoming	8	1	19.19%

Note: Standard errors derived as per U.S. Census Bureau (2010).

All numbers in thousands, and rounded independently.

Emigration Rates

The emigration rates used to construct our estimates are derived from Ahmed and Robinson (1994). Their 10-year rate of 18.7 percent for the decade of the 1980s was extrapolated to single years of entry. Although annual emigration rates are assumed to decline after entry, the overall 10-year emigration rate is maintained. National rates are assumed to apply to each state. The emigration rates we used were 3.0 percent for legal residents in their first year in the U.S. and 3.2 percent for unauthorized residents in their first year of residence. The rates decrease gradually with length of residence, dropping to 1.9 percent for legal residents after 10 years in the U.S and 2.0 percent for unauthorized residents after 10 years in the U.S.

To determine whether Ahmed and Robinson’s (1994) estimates are still applicable for more recent years, we conducted supplementary analyses (the results of which are available upon request) using data for the foreign-born population collected in the 2005 through 2009 ACS. This analysis indicates that national emigration rates at the end of the estimation period were at about the same level as in the earlier period. Supplementary analysis of ACS data for the ten states with the largest foreign-born populations in 2010 indicates that emigration rates for those states were at about the same level as the national rate.

Undercount Rates

The undercount rates we used were developed within the following logical framework: (1) the foreign-born population was more completely counted in the 2000 Census than in the 2010 ACS; (2) those with close attachments to the U.S. (legal immigrants) were more completely counted than unauthorized immigrants; and, (3) undercount rates decrease with length of time in the U.S.

For unauthorized immigrants who entered the United States in the 1990s, we used an overall undercount rate of 10.0 percent based on work by Marcelli and Ong (2002).^⁵ The most recent unauthorized entrants were adjusted by 11.5 percent, and the undercount rate decreased by about 5 percent per year. The legal immigrant population is composed of legal permanent residents (LPRs), refugees, and nonimmigrants. For LPRs and refugees that entered the U.S. in the 1990s, we used a rate of 2.5 percent, or one quarter of the rate for unauthorized residents. For nonimmigrant residents, we used an undercount rate of 5.0 percent, which is twice the rate used for LPRs and refugees.^⁶ This produced an undercount rate of 3.0 percent for total legal immigrants at the national level.

As noted above, we assumed that undercount rates were higher in the 2010 ACS than in the 2000 Census because the ACS does not have the resources – money, publicity, extensive follow-up, etc. – that decennial censuses have. We set the undercount rate at 20 percent for the most recently arrived cohort of unauthorized residents in the 2010 ACS and then reduced the rates by 10 percent per year. The overall undercount rate for unauthorized residents that entered in 2000 to 2009 was thus estimated to be 12.1 percent.^⁷ For LPRs and refugees that entered from 2000 to 2009, we doubled the 2000 rate of 2.5 percent to 5.0 percent. The rate of 15 percent used for nonimmigrant residents brought the overall rate for legal immigrants for 2000 to 2009 up to 5.3 percent.

Methods

In Tables 1 through 3, we illustrate the methods we use to compute annual estimates of the unauthorized immigrant population and components of change in that population for 1990 through 2010. These tables present national estimates; figures in them are aggregated up from 51 parallel sets of state tables (which appear as Appendix Table A3).

Table 1

Annual Estimates of the Foreign-born Population Residing in the United States, by Legal Status and Year of Entry: 2000 to 2009

	Foreign-born Population in January 2010				Unauthorized Immigrant Population in January 2010	Left the Unauthorized Immigrant Population (via Emigration, Removal by DHS Adjustment to Lawful Status, or Death)
Year of Entry	Total (ACS)	Legally Resident	Unauthorized	Undercount	Unauthorized Immigrant Population in January 2010	2009	2008	2007	2006	2005	2004	2003	2002	2001	2000	Entry cohorts

	(1)	(2)	(3)= (1)-(2)	(4)	(5)= 3+4¹	(6)	(7)	(8)	(9)	(10)	(11)	(12)	(13)	(14)	(15)	(16)= Σ(5–15)^¹
Total	12,775	7,441	5,334	733	11,725	558	549	531	482	476	474	493	473	508	369
2009	1,136	819	307	77	384	-	-	-	-	-	-	-	-	-	-	384
2008	1,162	885	317	70	387	53	-	-	-	-	-	-	-	-	-	439
2007	1,245	848	386	75	461	43	54	-	-	-	-	-	-	-	-	558
2006	1,238	762	516	88	604	42	47	56	-	-	-	-	-	-	-	749
2005	1,478	762	596	90	686	38	44	49	57	-	-	-	-	-	-	873
2004	1,212	737	537	72	609	32	36	40	44	52	-	-	-	-	-	813
2003	1,135	653	499	59	558	30	31	33	37	41	50	-	-	-	-	779
2002	1,188	631	577	61	638	34	32	33	35	39	45	51	-	-	-	906
2001	1,368	655	727	68	795	44	38	37	37	41	46	50	58	-	-	1,146
2000	1,615	690	872	73	945	50	48	43	40	43	47	53	57	65	-	1,389

Pre`00	-	-	-	-	5,658	192	220	241	234	261	286	339	358	443	369	8,600

All numbers in thousands, and rounded independently.

¹Except for the shaded area

Estimates for 2000 to 2010

Using 2010 ACS data, Column 1 in Table 1 reports estimates of the total foreign-born population, separately by year of entry between 2000 and 2009. For example, the ACS included about 1,188,000 foreign-born people who entered the country in 2002, and about 12,775,000 foreign-born people who entered in any year between 2000 and 2009. For some states, an adjustment was made to correct the apparent overstatement of the 2000 entry cohort in the ACS.^⁹ Column 2 reports the size of the legally resident foreign-born population, separately by year of entry between 2000 and 2009, including immigrants admitted for permanent residence, refugees, and nonimmigrant residents; as described above and in Appendix Table A1, these figures are based primarily on administrative data collected by DHS and other federal agencies. Column 3 presents the estimated number of unauthorized immigrants who were included in the ACS, separately by year of entry between 2000 and 2009. The estimates in Column 3 are residual estimates (Column 1 minus Column 2) that have been smoothed slightly to reduce the effects of sampling variation.^¹⁰ Column 3 indicates that about 5,334,000 more foreign-born individuals were counted in the ACS as arriving between 2000 and 2009 than were legally admitted during those years. Column 4 introduces an adjustment for undercount in the ACS; for reasons described above, assumed undercount rates vary across entry cohorts, ranging from 20.0 percent for 2009 to 7.7 percent for 2000 and averaging 12.1 percent. Finally, Column 5 reports the total unauthorized immigrant population living in the U.S. in January 2010, by year of entry between 2000 and 2009; the derivation of the estimate for “Pre-00” is described below. The top line of Column 5 in Table 1 indicates that there were about 11,725,000 unauthorized immigrants living in the U.S. in January 2010.

The next step in constructing Table 1 is to determine how many unauthorized immigrants left the population each year between 2000 and 2009 (as shown in Columns 6 through 15), separately by year of entry. Unauthorized immigrants can leave the population in four ways—emigration, removal by DHS, adjustment to lawful status, or death. Our sources of information for these components are described above and in Appendix Table A1. For example, among foreign-born individuals that entered the U.S. in 2005, Column 9 of Table 1 indicates that about 57,000 left the U.S. (one way or another) in 2006. The last step in constructing the non-shaded area of Table 1 was to estimate the size of each annual cohort in its actual year of entry. Each entry cohort in Column 16 was estimated by summing Columns 5 to 15. In essence, we started with the population in January 2010 (Column 5) and “added back” those who left the population between entry and January 2010.^¹¹ For example, Column 5 of Table 1 shows that in January 2010 there were about 461,000 unauthorized immigrants living in the U.S. who entered in 2007. Columns 6 and 7 show that a total of 97,000 unauthorized immigrants who entered the country in 2007 subsequently left that population (54,000 in 2008 and 43,000 in 2009). Consequently, we estimate that 461,000 + 43,000 + 54,000 = 558,000 unauthorized immigrants entered the country in 2007. The top line of column 8 shows that 531,000 unauthorized immigrants left that population in 2007; this implies a net change of 558,000 – 531,000 = +27,000 unauthorized immigrants in 2007.

The shaded area at the bottom of Table 1 pertains to unauthorized immigrants who entered the country prior to 2000. The beginning point is the estimated unauthorized immigrant population of 8.6 million in January 2000, shown at the bottom of Column 16; this figure is taken from Table 2, as described below. The number of unauthorized immigrants who arrived prior to 2000 and who left that population in each year between 2000 and 2009 (the shaded areas of Columns 6 to 15) was subtracted from 8.6 million. That yields an estimate of 5.7 million unauthorized immigrants who moved to the United States before 2000 and still lived here in January 2010 (the shaded area of Column 5 in Table 1). Adding 5.7 million to the other numbers in Column 5 produces our estimate of 11,725,000 unauthorized immigrants living in the United States in January 2010.

Estimates for 1990 to 1999

Estimates for 1990 to 1999 were computed using data from the 2000 Census and the same methodology described above. Details are presented in Table 2. Our estimate of 3,500,000 unauthorized immigrants in 1990—the figure in Column 16 of the shaded area of Table 2—is based on estimates produced by Warren (1997). Columns 6 through 15 of the shaded area in Table 2 show that of the 3.5 million unauthorized immigrants living in the U.S. in 1990, 1.25 million left by 2000, yielding 2.25 million who arrived in the U.S. prior to 1990 and who still lived in the U.S. in 2000. The un-shaded portion of Column 5 in Table 2 shows the number of unauthorized immigrants who entered the U.S. in each year between 1990 and 1999 and who still lived in the U.S. in 2000. After “adding back” individuals in each year-of-entry cohort who left the population of unauthorized immigrants (the un-shaded portions of Columns 6 through 15 in Table 2), Column 16 reports the total size of each annual entry cohort between 1990 and 1999.

Annual Estimates of Population Size and Components of Change, 1990 to 2010

The first four columns of Table 3 were constructed entirely from the estimates reported in Tables 1 and and2,2, but the numbers have been put into a more familiar form. Table 3 also includes detailed information about the method by which unauthorized immigrants left that population, by year of entry. The headings for Columns 2, 3 and 4 show the sources of the estimates. Column 1 in Table 2 begins with the estimate of 3.5 million unauthorized immigrants in January 1990 (Table 2, Column 16, shaded area), and annual estimates were then computed for subsequent years by comparing the size of annual entry cohorts (Column 3) to the annual number leaving the unauthorized immigrant population (Column 4) to produce annual estimate of net change in the unauthorized immigrant population. For example, we estimate that there were 11,899,000 unauthorized immigrants on January 1, 2009 (Column 1). During 2009, we estimate that 384,000 unauthorized immigrants entered the U.S. (Column 3) and 558,000 left that population (Column 4). Thus there was a net change of 374,000 – 558,000 = −174,000 unauthorized immigrants in 2009, and the population of unauthorized immigrants on January 1, 2010 equaled 11,899,000 – 174,000 = 11,725,000.

Table 3

Estimates of the Total Unauthorized Immigrant Population of the United States and Annual Components of Population Change: 1990 to 2010

					Method of Leaving e Population
Year	Unauthorized Immigrants, January 1	Annual Net Change	Entered the Population²	Left the Population³	Emigrated	Adjusted to Lawful Status⁴	Removed by DHS	Died

	(1)	(2) = (3)–(4)	(3)	(4)=Σ(5 to 8)	(5)	(6)	(7)	(8)
2010	11,725
2009	11,899	(174)	384	558	243	104	165	46
2008	12,009	(110)	439	549	252	100	150	46
2007	11,981	27	558	531	258	94	133	46
2006	11,714	267	749	482	256	64	117	45
2005	11,317	397	873	476	250	79	103	44
2004	10,978	339	813	474	247	84	100	42
2003	10,692	286	779	493	244	120	88	41
2002	10,259	434	906	473	237	115	81	40
2001	9,620	638	1,146	508	223	176	71	37
2000	8,600	1,020	1,389	369	198	73	65	33
1999	7,827	773	1,132	358	198	60	65	35
1998	7,210	616	954	338	182	61	65	30
1997	6,763	448	759	311	170	54	59	28
1996	6,291	472	756	284	161	55	41	26
1995	5,720	571	822	251	150	42	36	24
1994	5,253	467	700	233	138	38	35	22
1993	4,925	327	557	229	130	45	34	20
1992	4,587	339	559	220	124	43	34	19
1991	4,135	452	649	197	116	35	29	17
1990	3,500	635	816	181	103	38	25	15

¹From the shaded area of Table 2, Column 16.

²From Column 16 of Tables 1 and and22.

³From the top row of Columns 6 to 15 in Tables 1 and and22.

⁴Includes unauthorized residents that left the U.S., returned with immigrant visas, and were tabulated as new arrivals.

All numbers in thousands, and rounded independently.

Sampling Variability

Our estimates of the size and attributes of the foreign-born population are based on sample data from the 2000 Census and the ACS, and therefore our annual estimates of the unauthorized immigrant population are subject to sampling variability. In Appendix Table A2 we report estimates of the number of foreign-born people living in the U.S. and in each state who came to the U.S. between 2000 and 2009 along with standard errors of those estimates; the standard errors are computed as per the guidance of the U.S. Census Bureau (2010b). In contrast, our counts of the legally resident foreign-born population and of the number of unauthorized immigrants removed each year are not subject to sampling variability because they are based on administrative record data; therefore, we are unable to estimate a possible range of non-sampling error in the estimates of the legally resident population. Finally, our estimates of mortality and emigration are based on sample data and statistical models, but uncertainty in these estimates is difficult to quantify. Because of this mixture of types of data, we do not compute proper standard errors for our estimates. We suggest that relatively small year-to-year or state-to-state differences should be disregarded, and we caution that actual differences might be somewhat higher or lower than reported here. The standard errors reported in Appendix Table A2 may be useful for generating approximate confidence intervals and for describing uncertainty in our population estimates.

Results

Figure 1 is based on the estimates in Table 3, and depicts the annual number of unauthorized immigrants entering the United States (the top bars), the annual number leaving the country (the bottom bars), and net change in the population size (the line). The annual number moving to the U.S. increased in the 1990s, growing from about 550,000 in 1993 to 1.1 million in 1999. More than 1 million arrived each year from 1999 to 2001; 1.4 million arrived in 2000. After 2000, the number moving to the U.S. declined sharply, dropping by 72 percent from its peak in 2000 to about 400,000 in 2009.

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Figure 1

Annual Net Change and Components of Change in the Number of Unauthorized Immigrants in the U.S., 1990–2009

From 1990 to 2009, an estimated 15.7 million unauthorized immigrants moved to the United States. However, the population grew by “only” 8.2 million. This reveals an important aspect of unauthorized immigration that has typically been overlooked: Significant numbers of unauthorized immigrants leave the population each year. An estimated 7.5 million left the unauthorized immigrant population^¹² between 1990 and 2009. Although the rates of departure have remained fairly constant over the past two decades, the growing population has generated increasing numbers of departures. The total number leaving the population increased steadily from about 180,000 in 1990 to about 560,000 per year in 2009; as shown in Columns 5 to 8 of Table 3, each category of “departure” (i.e., removal, death, emigration, and adjustment of status) increased considerably between 1990 and 2009.

Annual net change in the unauthorized immigrant population is determined by the number entering minus the number leaving. As shown in Table 3 and Figure 1, population growth dropped from one million in 2000 to a net decline of 174,000 in 2009. A variety of factors might explain the sharp reduction in population growth in the past decade, including less favorable U.S. economic conditions after 2000, heightened security for air travel after September 11, 2001, and increased enforcement efforts by DHS. It is clear, however, that the substantial drop in arrivals after 2000 was the primary contributor to declining population growth and to reaching zero growth by the end of the decade.

The economic downturn in 2008 and 2009 apparently had little effect on emigration from the unauthorized immigrant population in those years. A set of estimates for January 2008, comparable to ours, estimated the unauthorized population that entered from 2000 to 2007 to be 5,187,000 (Hill and Johnson 2011). Two years later, those entry cohorts would have been reduced by emigration, adjustments to legal status, removals by DHS, and deaths.^¹³ However, as shown in Table 1, Column 5, our estimate for January 2010 for those same cohorts is 5,296,000 or about 2 percent higher than the comparable figure in 2008. The unexpected increase for 2010 compared to 2008 probably occurred because of coverage improvement in the 2010 ACS which is likely to be better enumerated because it was conducted in a census year. Still, these two estimates provide clear evidence that any increases in emigration rates in 2008 and 2009, if they did occur, were too small to have a discernible effect on the population estimates and patterns of growth described here. We will leave it to others to more fully analyze the determinants of the patterns observed in Figure 1. However, it would be difficult to do those analyses without annual estimates of inflows into, outflows from, and net change in the unauthorized immigrant population.

These results at the national level have a number of implications for developing immigration policy and for U.S. data collection efforts. First, even though the number of unauthorized arrivals has dropped significantly since 2000, hundreds of thousands continue to move to the United States each year. Second, departures from the unauthorized immigrant population are an important aspect of population change for this group. Third, improvements in the data sources are needed to update and expand the empirical basis for future estimates. Fourth, the ACS has proven to be a vital resource for deriving detailed national and state estimates of the unauthorized immigrant population.

State Estimates

Appendix Table A3 shows estimates for each state that are comparable to the figures shown in Table 3 for the country as a whole: The size of the unauthorized immigrant population each year, the number entering that population each year, the number exiting that population each year (through emigration, death, removal, and adjustment of status), and annual net change in the size of that population.^¹⁴

Figure 2 shows estimates for the 25 states with the largest unauthorized immigrant populations in January 2010. More than half of all unauthorized immigrants lived in California (2.9 million), Texas (1.6 million), Florida (1.0 million), and New York (705 thousand) in 2010. The temporal trends in inflows, outflows, and net change in the size of the unauthorized immigrant population observed in Table 3 and Figure 1 for the total U.S. population occurred in most, but not all, of the states. In Figure 3, we depict temporal trends in inflows, outflows, and net change in population size for the six states with the largest unauthorized immigrant populations in 2010: California, Texas, Florida, New York, Illinois, and New Jersey. As in the country as a whole, in each of these states the inflow of unauthorized immigrants rose in the 1990s, peaked in about 2000, and declined steadily thereafter.^¹⁵ Outflows from the unauthorized immigrant population increased gradually over time; and thus net change after 2000 declined to a point near or below zero in 2010. Between 2000 and 2009, every state (except Mississippi)^¹⁶ and D.C. saw declines in inflows of unauthorized immigrants, and every state saw increases in outflows between 2000 and 2009. As a result, 29 states and D.C. experienced net losses in 2009 in the size of their unauthorized immigrant populations. As shown in Figure 4, only four states had net gains of 4,000 or more unauthorized immigrants in 2009, while the combined populations of California, New York, and Texas declined by more than 165,000.^¹⁷

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Figure 2

Number of Unauthorized Immigrants, by State, January 2010

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Figure 3

Annual Net Change and Components of Change in the Number of Unauthorized Immigrants, Selected States, 1990–2009

Note: The vertical scale of the figures for California, Texas, and Florida (in the top row) is different from the vertical scale for New York, Illinois, and New Jersey (in the bottom row). In all figures, the lines (representing net change in population size) are scaled according to the vertical axis on the right. The bars (representing entries and exits) are scaled according to the vertical axis on the left.

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Figure 4

States with the Largest Net Changes in Populations of Unauthorized Immigrants, 2009

The seven states with the fastest growing populations of unauthorized immigrants over the past two decades, in declining order, were in the southeast: Alabama, South Carolina, North Carolina, Tennessee, Arkansas, Kentucky, and Georgia. In each of these states, the unauthorized immigrant population was more than 11 times larger in 2010 than it was in 1990; by contrast, the total U.S. unauthorized immigrant population tripled in the 1990 to 2010 period. In 1990, these seven states were home to just 2.5 percent (about 90,000) of the total unauthorized immigrant population; by 2010, the seven states had 10.4 percent (1.2 million) of the U.S. total. Yet despite the very rapid growth in these states from 1990 to 2010, the percent of unauthorized to total residents in the seven-state area in 2010 was still well below the same percent for California. In these seven states, the 1.2 million unauthorized residents in 2010 made up 2.9 percent of the total resident population of 42.3 million. In California, the 2.9 million unauthorized residents in 2010 constituted 7.9 percent of the total resident population of 37.3 million.

Qualifications and Sensitivity Analyses

As described above, our estimates are more statistically reliable than those produced by Pew and OIS and they include detailed information about inflows, outflows, and net change in each year and by state. However, three potential methodological issues regarding our estimates are worth exploring.

First, the basic logic of the residual method identifies the number of unauthorized immigrants by subtracting the number of authorized immigrants from the total foreign-born population. Precise counts of the legally resident population should—but in our estimates do not—include: (1) asylees and parolees who have work authorization but who have not adjusted to permanent resident status; (2) aliens who have filed Form I-485 (Application to Register Permanent Residence or Adjust Status) and who have been given work authorization pending final approval of legal permanent resident status; and (3) aliens who are allowed to remain and work in the United States under various legislative provisions, such as Temporary Protected Status. Unfortunately, current estimates are not available for these groups; estimates for 2000 totaled 577,000 people (Warren 2003). Because we are likely modestly understating the number of authorized immigrants, we are also likely modestly overstating the number of unauthorized immigrants.

Second, we are not able to quantify the migration of authorized immigrants between U.S. states. For our purposes, the state of residence of authorized immigrants is generally the state in which they lived when they entered DHS’s databases. Subsequent changes of residence to other states typically are not recorded. Net internal migration of both authorized and unauthorized immigrants within the U.S. after admission could affect the accuracy of our estimates of unauthorized immigration for individual states. We discuss the issue of internal migration in more detail at the end of this section.

Third, as described above, the methodology used to generate our estimates is based on assumptions about (1) mortality rates among the foreign born; (2) rates of emigration from the United States; and (3) undercount rates in the Census and ACS. Although we cannot know any of these rates with precision, in this section we quantify the sensitivity of our estimates to alternative assumptions about each of these rates. How much would our national estimate of 11.7 million unauthorized immigrants in January of 2010 change under alternate assumptions about the three sets of rates?

Mortality

Because of their relatively youthful age distributions, authorized and unauthorized immigrants have crude death rates that are lower than the rate for the entire U.S. population. Consequently, alternative assumptions about death rates have very little impact on our estimates. Increasing the crude death rate for the unauthorized immigrant population by 25 percent would reduce our estimate of the unauthorized immigrant population by only 81 thousand, or 0.7%. Increasing the crude death rate for the authorized immigrant population by 25 percent would increase the total unauthorized population by 90 thousand, or 0.8%. As noted above, the effects of increasing or decreasing mortality rates for both authorized and unauthorized immigrants would be offsetting.

Emigration and Undercount

Assumptions about emigration and undercount have greater potential for biasing our estimates. Table 4 shows the amount and percent that our estimate of total number of the unauthorized immigrants would change if alternative assumptions about emigration and undercount—plus or minus 25 percent in both cases—were used to construct that estimate. In general, even these extreme alternative assumptions about emigration and undercount would change our estimate of 11.7 million by only plus or minus 400,000 or about 3.5 percent.

Note that all of these sensitivity analyses pertain to our point estimate of the total size of the unauthorized immigrant population. The discussion above provides considerable support for our assumptions about mortality, emigration, and undercount rates. Reasonable variations in these assumptions would not matter a great deal for the sorts of temporal trends shown in Figure 1 or in parallel figures for states.

Net internal migration

To take account of internal migration would require detailed data on net internal migration for each state, by year of entry, compiled separately for legal and unauthorized immigrants; unfortunately, the necessary information is not available. DHS takes account of internal migration of part of the legal resident population by using data on the residence of the naturalized population; PEW takes account of internal migration of legal residents by using state-to-state migration rates for six states (CA, TX, NY, FL, IL, and NJ) and “all other” from the CPS and assuming that the rates for all foreign-born apply to the estimates of legal residents by state.^¹⁸

There are three reasons why the effects of net internal migration of legal residents on our estimates could be relatively small. First, the majority of LPRs are admitted on the basis of close kinship with U.S. relatives, possibly reducing their odds of subsequent out-of-state moves. Second, a substantial proportion of the legally resident population already had a residence in the U.S. at the time they entered the DHS data systems, for example by adjusting from temporary to permanent lawful residence. Third, the legal immigrants and refugees in our estimates have, on average, only five years of residence in the U.S., reducing the time they have to migrate compared to those who have been here for longer periods.

Discussion

We estimate that about 11.7 million unauthorized immigrants lived in the United States in January of 2010.^¹⁹ This figure is likely a modest overestimate (by perhaps a few hundred thousand) because data are not available for some (relatively smaller) portions of the authorized immigrant population (who are thus counted as unauthorized). More than half of all unauthorized immigrants lived in California, Texas, Florida, and New York. The number of unauthorized immigrants coming to the U.S. grew steadily in the 1990s, declined between 2000 and 2003, and then continued to decline rapidly after 2005. From 2000 to 2009, arrivals of unauthorized immigrants to the U.S. dropped from about 1.4 million to 400,000, a decline of 72 percent. While there is a great deal of publicity about the number of unauthorized immigrants who enter the U.S. each year, it is important to reiterate that many unauthorized immigrants also leave that population each year—well over half a million in 2009. Because of declining inflows after 2000 and steadily increasing outflows since 1990, annual net change in the size of the unauthorized immigrant population has also declined—indeed, it was negative in 2008 and 2009. That is, since 2007 the United States has lost more unauthorized immigrants than it has gained. It should be noted, however, that even though the unauthorized immigrant population in the U.S. has essentially reached zero growth, unauthorized immigration to the United States continues at a high level – nearly 400,000 arrived in 2009.

The annual time series for every state can be used in conjunction with other data collected by the Census Bureau to analyze trends in immigration since 1990. The estimates will complement any analysis of immigration trends carried out at the state level.^²⁰ For example, in her discussion of immigration to gateway states, Singer (1994) shows state-by-state estimates of the percent change in the foreign-born population from 1990 to 2000. Using our estimates, Table 2 in that report could be revised to show comparable estimates for legal and unauthorized residents in each state. Then, those tables could be updated to show change from 2000 to 2010.

Although additional analyses are beyond the scope of this article, we can illustrate some of the implications of these estimates by focusing on the seven rapidly growing states in the southeast.^²¹ On the broadest scale, the size of the unauthorized population in these seven states in 2010 might not appear to be remarkable – even after growing very rapidly for 20 years, unauthorized immigrants make up just 2.9 percent of all residents, well below the U.S. average of 3.9 percent. When we expand the analysis to include census data for the foreign-born population, we begin to see additional effects of unauthorized immigration to the seven states. In 1990, the percent of foreign-born that were unauthorized was the same in the seven states as it was nationally, about 18 percent. From 1990 to 2010, the percent of the foreign-born that were unauthorized jumped from 18 percent to forty seven percent in the seven states. In other words, in 1990 the foreign-born population in the seven states was small, about 500,000, and fewer than one in five were unauthorized residents. By 2010, the foreign-born population had quadrupled to 2.6 million, and nearly half of them were unauthorized.

As described above, our estimates (as are those from OIS and Pew) are based on assumptions about mortality rates, emigration rates, and rates of undercount in the Census and ACS. As demonstrated above, our point estimates—at least at the national level—change only modestly if we make fairly extreme alternative assumptions about those rates. Our inferences about trends over time are likely unaffected by these assumptions. Nonetheless, our estimates could be improved by refinements in techniques for measuring emigration and undercount rates. Indeed many important policy and academic questions could be much more readily addressed if the Census Bureau would implement the pending U.S. General Accounting Office (GAO1998) recommendation that the Census Bureau and the Immigration and Naturalization Service (now DHS) devise a plan of joint research to evaluate the quality and completeness of census and survey data on the foreign-born population in the United States. In addition, DHS should improve its collection of data on the arrival and departure of all nonimmigrants.

The quality of our estimates is certainly limited by the accuracy and completeness of the data on which they are based; besides the assumptions about mortality, undercount, and emigration that are built into our estimates, they are still also subject to random sampling error. Note, however, that amid all of the speculation and attempts to estimate the size of the unauthorized immigrant population over the years, the methodology used here is the only one that has been tested empirically. When IRCA was enacted in 1986, the U.S. Government needed to know how many might come forward for legalization so that it could set up legalization offices across the country. The Statistics Division of what was then called the Immigration and Naturalization Service, using methods similar to the ones used here, projected that the number of pre-1982 applicants for legalization would range from 1.3 to 2.7 million. A total of 1.6 million in this group came forward. In the large majority of cases, the projected high and low ranges for individual states bracketed the numbers that actually applied for legalization. A difference between the data and methods used here and those that performed so well at the time of IRCA is that both the methods and data sources have been improved significantly since 1987.

Our estimates of the total number of unauthorized immigrants in the U.S. and in larger states are comparable to those produced over the past few years by Pew and DHS. The similarities in these estimates are remarkable given the differences in data sources and methods used to derive them. Overall, however, our data and methods produce estimates with smaller ranges of sampling error compared to those produced by Pew, and we show estimates for all of the states and D.C. instead of just the top ten states produced by DHS. We also provide a longer time series, covering every year between 1990 and 2010. Finally, an important and unique strength of our estimates is that we quantify inflows into and outflows from the unauthorized immigrant population at both the state and national levels. This makes possible any number of policy and academic analyses of the factors that influence inflows, outflows, and net change and of the economic, social, political, demographic, and other consequences of those trends.

Footnotes

This report and the estimates herein would not have been possible without the contributions of Michael Hoefer and his staff in the DHS Office of Immigration Statistics and the staff of the Immigration Statistics Branch in the U.S. Census Bureau’s Population Division. We are also grateful for assistance from Karl Eschbach, Linda Gage, Hans Johnson, Carolyn Liebler, Joe Salvo, Vicky Virgin, and several anonymous reviewers. All errors and omissions, however, are the responsibility of the authors.

¹Passel (1986) and others distinguish between “analytic” estimates—those based on systematic analysis of publicly available data—and “speculative” estimates based on conjecture and/or the misuse of data. In this article, we are only concerned with analytic estimates. Although speculative estimates—such as those by Elbel (2007) and Justich and Ng (2005)—often receive as much public attention as analytic estimates, they are not subject to verification or methodological improvement.

²Less attention is paid to estimates of the number of unauthorized immigrants who leave the U.S. each year (Ahmed and Robinson 1994; Van Hook and Zhang 2011; Warren and Peck 1980).

³One exception is Warren (1994), whose national estimates were based on data from the Immigration Reform and Control Act (IRCA) legalization program, estimates of nonimmigrant overstays, and estimates for Mexico based on the residual method.

⁴Nonimmigrants are non-citizens admitted legally for specified temporary periods. Examples include foreign students, temporary workers, intra-company transferees, and others, including family members. These estimates include only those nonimmigrants that would be expected to be counted in censuses and surveys.

⁵Our assumed undercount rate of 10.0 percent in the 2000 Census for unauthorized immigrants who entered in 1990 to 1999 is comparable to estimated undercount rates for two of the most difficult-to-measure populations in the 2000 Census: (1) Hispanic males age 16 to 29 (10 percent) and age 30 to 49 (15 percent) (U.S. Census Bureau 2010a: Table 4) and (2) Black males age 18 to 49 (8.3 percent) (U.S. Census Bureau 2001: Appendix Table B3). In addition, in constructing an estimate of the unauthorized immigrant population originating from Mexico for 1996, the Mexico-United States Binational Migration Study “set plausible underenumeration rates for the legal and unauthorized Mexican populations at 4 and 12 percent respectively” (Bean et al. 1998: 79).

⁶A higher rate of undercount was used for nonimmigrant residents compared to LPRs and refugees because nonimmigrants are recent arrivals with relatively less experience and less attachment to the U.S. and thus they would be more difficult to enumerate.

⁷Our overall undercount rate of 12.1 percent for unauthorized immigrants that entered from 2000 to 2009 is consistent with the rates used by Pew and OIS. Pew has developed a set of assumptions consistent with the available information from census-based studies and with historical demographic data from Mexico. The undercount rates are higher for countries where the population is largely Latino, for young adult males and for recent arrivals. Overall, in 2008, these assumptions resulted in an estimated undercount of 12.5% for unauthorized immigrants in the March CPS. In deriving their estimates, DHS assumes that 10 percent of unauthorized immigrants are omitted from the ACS.

⁸The estimates in column 1 of Table 1 are from the 2010 ACS, which is the first ACS to be controlled to the results of the 2010 Census. Comparisons of the results presented here with similar estimates for July 2009 – based on ACS data controlled to the 2000 Census – indicate that shifting the ACS controls from the 2000 census to the 2010 ACS increased the estimated unauthorized immigrant population by between 750,000 and 1 million.

⁹Specifically, we adjust for “heaping”— the tendency for respondents in censuses and surveys to erroneously select years ending in zero or five when reporting their age or year of entry. It was apparent from examining the ACS data and from the pattern of annual estimates produced by the unadjusted ACS data that there was a considerable amount of heaping on the year 2000. For each state, the size of the 2000 entry cohort used in these estimates was limited to no more than 25 percent above the average of the 2001 and 2002 entry cohorts. The amount that the 2000 entry cohort exceeded the limit was judged to be due to heaping.

¹⁰For the nine states that have the smallest unauthorized immigrant populations, the size of each residual estimate shown in column 3 was set to be (1) at least as large as the estimated legal population and (2) no larger than twice the percent of unauthorized to total foreign-born estimated for the State in the 1995 to 1999 period. These limitations added logical consistency to the estimates and tended to smooth the annual entry cohorts.

¹¹The description above is conceptually accurate, but the actual calculations were done differently. The size of each entry cohort shown in Column 16 is defined as, “the number that will produce the figure in Column 6 after being reduced by the four components of change each year.” Because estimated emigrants and deaths are based on rates, it was necessary to use an iterative process to derive the numbers shown in Column 16. This estimation procedure assures that unauthorized immigrants that entered the U.S. during each year of the decade, and then left the population before the end of the decade, are taken into account in the estimates.

¹²It is important to note that the phrase “leaving the unauthorized resident population, “ as used above, does not refer to internal migration within the United States. The term “emigration” above refers to movement out of the United States. Below we discuss the issue of internal migration in more detail.

¹³If emigration rates of unauthorized immigrants from 2008 to 2010 had been about the same as the rates we used, the cohort would have declined by about 11 percent.

¹⁴We provide Appendix Table A3 here to facilitate the peer review process. We anticipate that this lengthy table will be made available on-line, not in print, once this article is accepted for publication.

¹⁵In the large majority of states, the patterns of estimated arrivals and, consequently, net change in the unauthorized immigrant populations show peaks in 1990, 1995, 2000, and 2005. While this pattern could reflect actual peaks in inflows, especially in 2000, these peaks at 5-year intervals probably also reflect an unknown amount of “heaping,” which is the tendency for respondents to choose dates ending in 0 or 5.

¹⁶Estimated inflow to Mississippi increased from 1,418 in 2000 to 2,315 in 2009.

¹⁷There are certainly exceptions to the patterns described above. For example, in Alabama, Louisiana, Mississippi, and Oklahoma, inflows continued at high levels from 2002 through 2009. The annual inflow to Tennessee was about 13,000 from 1999 to 2007 and then declined in 2008 and 2009. We will leave it to others to explore the reasons for various regional and state-specific exceptions to the general patterns described above.

¹⁸The DHS or PEW procedures would not be applicable to our estimates. The naturalization data would not cover the majority of our legal resident population because, on average, our legal immigrant population resided in the U.S. for only 5 years, which is about the length of time that would be needed to naturalize. The PEW assumption that the rates for all foreign-born apply to legal residents has not been tested empirically. In fact, there are plausible reasons, described in the text, to believe that legal immigrants, especially the recently arrived immigrants in our estimates, have relatively lower rates of internal migration than the rest of the foreign-born population.

¹⁹As noted above, these estimates were derived using 2010 ACS data that are consistent with the 2010 Census count. As a result, they are approximately 750,000 to one million higher than other recent estimates that were based on 2000 Census counts. Explanation of the differences in the foreign-born population caused by changing from 2000- to 2010-based ACS population controls is beyond the scope of this article.

²⁰Studies of trends in immigration, by category of migrants, would be improved considerably if methods were devised to estimate unauthorized immigration below the state level.

²¹Of all the states and D.C, the seven with the highest ratios of unauthorized immigrants in 2010 compared to 1990 are: Alabama, Arkansas, Georgia, Kentucky, North Carolina, South Carolina, and Tennessee. The ratios range from 12:1 for Georgia to 19:1 for Alabama.

Contributor Information

Robert Warren, Former Director, Statistics Division U.S. Immigration and Naturalization Service.

John Robert Warren, Minnesota Population Center, Department of Sociology, University of Minnesota.

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PMC

Unauthorized Immigration to the United States: Annual Estimates and Components of Change, by State, 1990 to 2010

Robert Warren

John Robert Warren

Abstract

Review and Critique of Early Estimates

Review of Recent Estimates

Critique of Recent Estimates

Table 2

Table 4

Table A3

Research Design

Table A1

Data

Mortality Rates

Table A2

Emigration Rates

Undercount Rates

Methods

Table 1

Estimates for 2000 to 2010

Estimates for 1990 to 1999

Annual Estimates of Population Size and Components of Change, 1990 to 2010

Table 3

Sampling Variability

Results

State Estimates

Qualifications and Sensitivity Analyses

Mortality

Emigration and Undercount

Net internal migration

Discussion

Footnotes

Contributor Information

References

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