Immigrant Startups Continue to Grow
inc.com
inc.com
However, I think one can explain the statistics this way.
These are simply "average person" trends, and almost all U.S. businesses are still started by native-born Americans. Therefore, a "few" twenty and thirty year old Europeans moving to the US every year with a business idea would easily skew statistics. In fact, the only benefit or motivation to starting a business in most countries is simply that the dollar goes a long way in South America or Asia, and the Internet makes it possible for regular people to take advantage of that fact (as well as the entrepreneurship resources, blogs, and web sites.)
Also, according to last year's article (linked), this information is for any entrepreneurial activity, not just starting an actual business.