Republish from http://anepigone.blogspot.com/2009/04/percentages-of-countries-native.html
++Addition++John Derbyshire, who like Razib Khan epitomizes everything our approach to immigration should aim for, takes note at The Corner. I should point out, as Alex brings up in the comments, that the percentages are not of a country's total worldwide population that lives in the US--I do not have sufficient data for that. Instead, the table shows the population living in the US as a percentage of the total population currently living in the home country.
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The following table shows the the number of each country's native populace--by place of birth, not simply by descent--that is currently residing in the US as a percentage of that country's own resident population. Data are available here. All figures are from 2007: