Just to keep everyone using similiar data, using the 2009 attendance report:
MAGIC KINGDOM 17,233,000
EPCOT 10,990,000
HOLLYWOOD STUDIOS 9,700,000
ANIMAL KINGDOM 9,590,000
SEAWORLD FL 5,800,000
UNIVERSAL STUDIOS 5,530,000
ISLANDS OF ADVENTURE 4,627,000
BUSCH TAMPA BAY 4,100,000
6 FLAGS GREAT ADV. 2,634,000
6 FLAGS MAGIC MOUNT. 2,500,000
6 FLAGS GREAT AM. 2,500,000
So to the above statement about IOA doing more than the top three six flags combined that is not true.