http://en.wikipedia.org/wiki/List_of_attendance_figures_at_domestic_professional_sports_leagues
NFL in America - total attendence = 17,341,012 average 67,738
Basebal US - total attendance = 79,502,524, average 32,785
Premier league - English soccer = 13,094, 307 average 34,459
AFL - 7,050,945 average = 38,113
Baseball leads total attendance by a country mile. More than ten times as much as AFL and almost fives times as much as English soccer. American football has the highest average. Australian football has the second highest average. German soccer has the fourth highest average.
It seems you need to provide the best to keep the fans. In the age of globalisation, 2nd and 3rd rate leagues just don't cut it.
But Major League baseball stages about 14,000 games per season! (excuse the slight exaggeration). Of course its accumulative attendance figures are going to be that high!
I was only questioning your reference to overall average attendances, which, aside from everything else, paint the AFL in a fantastic light. To have an average in excess of 38,000, second only behind the NFL (where most stadiums hold between 65 and 85 thousand people), is a terrific effort.