The United States has manufactured something on the order of 8000 M-1 series tanks. I think only 2000 are actually in Active and Reserve units. The remainder, minus about 750-1000 or so sold overseas (Kuwait, Saudi, Egypt), are stored at POMCUS sites in Europe, Quatar, Kuwait, Diego Garcia, Okinawa and CONUS.
I don't have firm numbers, though. 8000 heavy tanks should keep the US going for a while, though.
[ 04-11-2001: Message edited by: fytinghellfish ]