Well, I learned something that does not surprise me to the least: according to CNN Americans know very little about religions, even their own, and the more religious they are the less they know. It seems that agnostics and atheists (if one can make the distinction between the two) have much better results. I don't think we should make fun of the Americans about it: I have seen how young believers here lack religious culture too. My brother witnessed the same thing with his teenage students.
I don't want to sound smug, but I did the quiz and I scored 8 out of 10. But I was tired and not paying much attention, so I think I could have had a perfect 10 (without false modesty). In any case, it is highly ironic that those who should know about the particulars of their faith know so little, if anything.