Survey says: "18% of children thought Aslan was a giraffe".
From the Guardian:
A new survey from the University of Worcester, conducted online on 500 children between the ages of seven and 14, has found that "classic children's literary heroes are dying out". Only 45% of the children questioned had heard of Alice in Wonderland and 8% of Mary Lennox. Nearly a fifth of the kids thought CS Lewis's wardrobe led to The Secret Garden, while 8% thought it led to Willy Wonka's Chocolate Factory; 10% thought Long John Silver was in Peter Pan and 18% thought Matilda lived in the Swiss Alps.
A bit more on the survey at the University of Worcester website.