I'm a Jackson fan, too, but I think a more fair way to compare those numbers is to use figures from movies an actor/actress was the top billing, or maybe even the top supporting role. But to say people went to see Jurassic Park because of SLJ is a little thin.
I didn't even know he was in the Incredibles (going to buy it this weekend) -- heck, half the time when I see him in a movie I'm like "I didn't even know he was cast in this film..."