These are the parks I have been too, in the order that I have ridden coasters at them (My first visits to some of these parks was when I was too small to ride coasters, or they didn't have coasters in the first place)
Luna Park Melbourne
Sea World
Dreamworld
Merimbulas Magic Mountain
Wonderland Sydney
Warner Bros Movie World
Wet 'n' Wild
Aussie World
Universal Studios Hollywood
Six Flags Magic Mountain
Disneys California Adventure
Disneyland
Knotts Berry Farm
SeaWorld San Diego
Universal Studios Orlando
Busch Gardens Africa
Islands of Adventure
SeaWorld Orlando
Disneys Hollywood Studios
Animal Kingdom
Magic Kingdom
Alton Towers
Blackpool Pleasure Beach
Thorpe Park
Chessington World of Adventures
Legoland
Adventure Island
So 27 (3.66 coasters per park)....Naturally it would be higher if I was including agricultural shows/exhibitions, and parks without coasters.