Very difficult to say.
Ironically many of them have been “Galt” from the beginning.
I wonder how many trespassing foreign nationals are in the official workforce as well as in the black market workforce?
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All Employment Growth Since 2000 Went to Immigrants
Government data show that since 2000 all of the net gain in the number of working-age (16 to 65) people holding a job has gone to immigrants (legal and illegal). This is remarkable given that native-born Americans accounted for two-thirds of the growth in the total working-age population.
http://www.cis.org/all-employment-growth-since-2000-went-to-immigrants
Immigrants gaining jobs, native-born Americans aren’t
Since the recession’s end in June 2009, legal and illegal immigrants posted a net gain of 656,000 jobs, while native-born Americans lost 1.2 million, says a Pew Hispanic Center report.
http://www.csmonitor.com/Business/2010/1029/Immigrants-gaining-jobs-native-born-Americans-aren-t