  The radial velocities of ~1800 nearby Sun-like stars are currently being
monitored by eight high-sensitivity Doppler exoplanet surveys. Approximately 90
of these stars have been found to host exoplanets massive enough to be
detectable. Thus at least ~5% of target stars possess planets. If we limit our
analysis to target stars that have been monitored the longest (~15 years), ~11%
possess planets. If we limit our analysis to stars monitored the longest and
whose low surface activity allow the most precise velocity measurements, ~25%
possess planets. By identifying trends of the exoplanet mass and period
distributions in a sub-sample of exoplanets less-biased by selection effects,
and linearly extrapolating these trends into regions of parameter space that
have not yet been completely sampled, we find at least ~9% of Sun-like stars
have planets in the mass and orbital period ranges Msin(i) > 0.3 M_Jupiter and
P < 13 years, and at least ~22% have planets in the larger range Msin(i) > 0.1
M_Jupiter and P < 60 years. Even this larger area of the mass-period plane is
less than 20% of the area occupied by our planetary system, suggesting that
this estimate is still a lower limit to the true fraction of Sun-like stars
with planets, which may be as large as ~100%.
