This is why we can’t have nice cheese: U.S. Limits Imported Cheese to Third of a Pound per American:
I searched a bit and discovered http://www.usitc.gov/publications/docs/tata/hts/bychapter/1210C04.pdf, which gives the import quotas for cheese by country. It turns out the annual aggregate amount is about 50 million kg of cheese from all countries. That works out to about one third of a pound per American. That’s only about 1/100th of total cheese consumption in the U.S., therefore that can legally be from a foreign country.
In other news, an average American eats 33 pounds of cheese every year. Holy shiitake mushroom.