Exactly... I chose 2003 because it is the first year with USF having IoA.
Again, taking numbers from @donsullivan (thank you for aggregating them!)
Attendance Comparison:
2003: WDW 37,700,000 USF 12,800,000
2009: WDW 47,513,000 USF 10,157,000
2014: WDW 51,490,000 USF 16,404,000...