You'd have to maybe go to mosques in Iran or do a poll among old ladies in Sicily to get numbers like this. Yet this is the American population. Just a couple of years ago, there was a study of what people thought of evolution. About half the population believed in divinely-guided evolution, Catholic church doctrine. Again, you've got to go back to pre-technological societies, or devastated peasant societies, before you get numbers like that.
Religious fundamentalism can be a very scary phenomenon.
It could be the mass base for an extremely dangerous popular movement. These fundamentalist leaders aren't stupid. They have huge amounts of money, they're organizing, they're moving the way they should, beginning to take over local offices where nobody notices them. It turned out that in many parts of the country ultraright fundamentalist extremists had been running candidates without identifying them. It doesn't take a lot of work to get somebody elected to the school committee.