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Prior to 2000, American degree production for citizens/permanent residents and employment growth for college grads were relative. The delta between college degrees and graduate employment was a shortfall 2,061,405 jobs in 2006.
The Unemployment level of College Graduates went from a low of 559,000 in 2001, to an all time high of 1,221,000 in 2004.
(NCES) Temporary Resident Degrees Awarded 2005
Master's = 73,223
Post Masters Certificates = 1,082
Doctor's = 14,342
Professional Degrees = 2,037
Professional Certificates = 260
Total = 90,944
The Employent-based (EB) green card program's quota is 120,120 -- and all visa are recaptured. Assuming all of the foreign postgraduates were interested in immigrating, the EB could handle all of the postgraduates at 75.5% of the quota.
NCES Graduation Data: Table 274. http://nces.ed.gov/programs/digest/d07/tables/xls/tabn274.xls
BLS Employment Data: http://data.bls.gov/PDQ/outside.jsp?survey=ln
Table 7. Awards conferred by Title IV institutions, by race/ethnicity, level of award, and gender: United States, academic year 2004-05 http://nces.ed.gov/pubs2007/2007167.pdf