The fraction of stars having nearly Earth-size planets

with any orbital period up to a maximum period,
P, on the horizontal axis. Only planets of nearly Earth size

are included. This cumulative distribution reaches 20.2% at
P = 50 d, meaning 20.4% of Sun-like stars harbor a 1–2

planet with an orbital period,
P < 50 d. Similarly, 26.2% of Sun-like stars harbor a 1–2

planet with a period of
P < 100 d. The linear increase in this cumulative quantity corresponds to planet occurrence that is constant in equal intervals of log
P. One may perform a modest extrapolation into the
P = 200–400 d range, equivalent to assuming constant occurrence per log
P interval, using all planets with
P > 50 d. Such an extrapolation predicts that

% of Sun-like stars have a planet with size 1–2

, with an orbital period between
P = 200 and 400 d.