I remember Pollstar saying they sold 91% of all available tickets, but I think that was worldwide. I saw 3 North American shows:
Columbus, about 51k tickets sold; I think capacity for PopMart was 72k, max? Certainly a lot less than for Pink Floyd's Division Bell show in the same venue.
Chicago, sold-out show, pre-renovation Soldier Field, maybe 48k?
Detroit, about 37k sold...which, believe it or not, was about 9k more than they drew in the same stadium for ZOO TV. Funny thing here was that they almost completely sold out the upper deck because tickets up there were $15 cheaper, I think.