Correction

According to the Rocky Mountain News/Denver Post (a combined single edition on the weekends), "Body Worlds 2 drew more than 680,000 people during its four month run, making it the third biggest exhibition ever at the museum."
Since I know of no other exhibits that were open for 24 hours with tickets sold out, my guess is that they have compared it to shows that were around longer.
The Museum has not disclosed how much money they keep from ticket sales but attendance resulted in double digit jumps in gift shop and concession revenue as well as a 20% spike in memberships.