Well, it depends on what you mean by "believe in creationism". For instance, the numbers they give don't really indicate where muslims, hindus, sikhs, native americans, buddhists, etc etc etc fit in. Depending on how the survey is worded, you can get a wide range of results. You also probably should differentiate between people who are hard-line creationists and people who believe that as their default but would freely admit that it doesn't have any evidence behind it (yes, such people exist). Also, I know xians who publicly toe the line but privately express doubts. the important things as far as I'm concerned are: 1) they're not the majority, 2) their numbers are going down, and 3) they're not able to teach it in school as a 'scientific theory'. (I'm all for teaching creationism in school, but in context).
Coffee is your friend. Everyone else is an acquaintance.