UPDATE:
As of the USCIS Stakeholders meeting of May 1, 2012, the top countries for EB-5 investors were, in descending order: China, South Korea, Taiwan, Iran and Venezuela. However, the exact figures were not publicized.
Korea, India, the United Kingdom, and Iran are all steady sources of EB-5 investors. Many observers view Mexico, Venezuela, Brazil, Vietnam, and India as potential 'hot' markets.
Korea and Venezuela are currently "hot" markets. Many predict that Brazil will soon become a "hot"market.
Russia is another 'hot' market for EB-5 investors.
Obviously China is the most popular EB-5 investor market, as it has more EB-5 investors than the next seven countries combined, according to the most recent figures (2010). To be more specific, after China, the 2010 figures have the Republic of South Korea, Great Britain/Northern Ireland, Taiwan and India rounding out the top five EB-5 markets.