..... Fifteen of the films: Snow White and the Seven Dwarfs, Pinocchio, Cinderella, Alice in Wonderland, Sleeping Beauty, The Sword in the Stone, The Jungle Book, The Little Mermaid. Beauty and the Beast, Aladdin, Pocahontas, The Hunchback of Notre Dame, Hercules, Mulan and Tarzan are all based on or were inspired by history, myth, cultural legend, or stories that have come into the public domain. Seven of the nine movies they released in the 1990's are in this list.
Three of the films: The Adventures of Ichabod and Mr. Toad (from The Legend of Sleepy Hollow), Robin Hood, and Oliver and Company (from Oliver Twist) are adaptations of stories similar to those in the previous (usually with the main characters changed into animals). One of the new movies is Treasure Planet, and even they admit that it's nothing more than Robert Louis Stevenson's Treasure Island retold in a science fiction setting. (The Lion King may also arguably be considered to be in this category as well (as a kid-friendly, Hollywood ending, pastiche of Shakespeare's Hamlet), but then again, the similarities are more archetypal than anything; it isn't similar enough to be a derived work.)
Eight of the films: Dumbo, Bambi, Peter Pan, Lady and the Tramp, 101 Dalmatians, The Many Adventures of Winnie-the-Pooh, The Black Cauldron, and The Great Mouse Detective, are all (probably) properly licensed animated adaptations of books, some well known, others less so. The new movie coming up in 2002, Return to Neverland is supposed to be a continuation of Peter Pan and might be lumped among these.
And let's not think about the flap they had over The Lion King and Kimba The White Lion, or how Atlantis: The Lost Empire is said to be suspiciously similar to Nadia: The Secret of Blue Water.
That makes a total of 28 films that have acknowledged sources outside of The Walt Disney Company itself, more than half of all the movies they've made to date.