In the New England Journal of Medicine is an article about the brain drain of physicians, The Metrics of Physician Brain Drain.. I heard about it on NPR. Check it out.

From the article:

"India, the Philippines, and Pakistan are the leading sources of international medical graduates. The United Kingdom, Canada, and Australia draw a substantial number of physicians from South Africa, and the United States draws very heavily from the Philippines. Nine of the 20 countries with the highest emigration factors are in sub-Saharan Africa or the Caribbean."