71 million wildlife watchers in U.S. in 2006.

That's roughly 1 in 3 Americans 16 and over, and more than four times greater than the attendance of all NFL games in 2006. $45.7 billion was spent that year on wildlife-watching activities, equivalent to revenue from all spectator sports, amusement parks and arcades, bowling centers, skiing facilities and casinos (except casino hotels.)

Source: U.S. Fish and Wildlife Service