Going by instant recognition and merchandise:
Winnie the Pooh
You get everything...
On the vid:
4 cinema movies
5 direct to dvd
3 different cartoon series
Yes, I know the character is from A. A. Milne.
Drawn first from E. H. Shepard.
But everybody recognizes Disney´s Pooh and not Shepard´s.
Edit: Damn it - the last 20 years. The first movie is from 1977. Sry
Sorry, it would than be Aladdin