Forgive the pun. Just some stats to consider for the future

Non-U.S. First-Year Physics Grad Students

Non-U.S. first-year physics grad students at U.S. universities are fractionally fewer than they used to be. Rising pretty steadily over the past 30 years to a high in 2001 of 53% among first-year physics graduate students, the foreign fraction dropped to 46% in 2003. The total number of first year students (US plus foreign) rose to 3076, the largest number since 1994. Who sends the most physics grad students to US departments? China accounts for 29% of the first year students in 2003, the India/Pakistan/SriLanka/Nepal/Bangladesh grouping accounted for 16%, Western Europe 13%, and Eastern and Central Europe 12%. (More information on the reason for the foreign fall-off, on sub-discipline choices, career expectations, fraction of women, sources of financial support, and so forth, can be gotten from the AIP report “Graduate Student Report: First-Year Physics and Astronomy Students in 2002 and 2003.

Doesn't surprise me at all

I don't think I had a physics grad assistant in either lecture or lab that was born in the United States