Also:
“The current law limits to 65,000 the number of foreign nationals who may be issued a visa or otherwise provided H-1B status each fiscal year (FY). Laws exempt up to 20,000 foreign nationals holding a masters or higher degree from U.S. universities from the cap on H-1B visas.”
http://en.wikipedia.org/wiki/H1B_visa
while:
“estimated growth rate of 700,000850,000 net unauthorized immigrants per year”
http://en.wikipedia.org/wiki/Illegal_immigrant_population_of_the_United_States
Both from Wikipedia.