The Pew Research Center released the results of their U.S. Religious Knowledge Survey yesterday. They polled some 3,412 Americans age 18 and older, asking them 40 questions that covered knowledge about Christianity, the Bible, other world religions, and a few general knowledge questions. Some of the key results:
On average, Americans correctly answer 16 of the 32 religious knowledge questions on the survey. [. . .]. Atheists and agnostics average 20.9 correct answers. Jews and Mormons do about as well, averaging 20.5 and 20.3 correct answers, respectively.
Protestants as a whole average 16 correct answers; Catholics as a whole, 14.7. Atheists and agnostics, Jews and Mormons perform better than other groups on the survey even after controlling for differing levels of education.
On questions about Christianity -- including a battery of questions about the Bible -- Mormons (7.9 out of 12 right on average) and white evangelical Protestants (7.3 correct on average) show the highest levels of knowledge.
Jews and atheists/agnostics stand out for their knowledge of other world religions, including Islam, Buddhism, Hinduism and Judaism; out of 11 such questions on the survey, Jews answer 7.9 correctly (nearly three better than the national average) and atheists/agnostics answer 7.5 correctly (2.5 better than the national average).
For a lot more information about the results (as well as the methodology) you can find the full report here.
If you're interested the Pew Research Center has an online survey you can take to compare your knowledge to the folks who took the survey.