ClinicalTrials.gov currently lists 133,939 studies with locations in all 50 states and in 180 countries.

Locations of Recruiting Studies

Recruiting Study Location Count Pie Chart
    Non-U.S. Only (49%)
    U.S. Only (45%)
    Both U.S. & Non-U.S. (7%)
Total N = 28,880 studies
Data as of October 11, 2012