The treemap chart above—part of the Pantheon project out of MIT Media lab—shows the birth countries of "globally known" sportspeople from 4,000 BC to 2010, i.e. sportspeople who are listed in the Wikipedias of at least 25 different languages. The U.S. and the U.K. come out on top, having produced 168 and 167 such athletes respectively.
MIT's extremely ambitious project aims to map the complete history of human cultural production from 4000 B.C. to present, and if you go over to the site you can play around with these parameters and generate your own charts (including charts that aren't treemaps, if you aren't into those.) Here's a chart showing globally known writers, from 4000 B.C to 2010:
And here are porn stars:
U-S-A! U-S-A!