BTW, the dollar amounts are kind of meaningless for non-US natives. For example, I'm from Argentina, where the US dollar has gone from 1 peso to thousands of pesos during my lifetime (it's now around 3 pesos, after several sheddings of zeroes in the peso's part).
well its mostly by class, the $$$ is for people who don't really know...if you are foreign born list whichever class your parents were, at the age of 22.