You can mine some of the data yourself by looking it up at
http://nces.ed.gov/programs/digest/d...s/dt04_283.asp
They have collected a lot of the data, I cannot specify how they did the collection though - some day I'll be bored enough to read through all their info. But using their info, it was about 59,000 in 2003. I know I've spouted off those numbers that FIRST (Dean, et al) gives us but I felt the NCES.ed.gov backed them up enough. Hmmm??