The Pew Research Center’s Forum on Religion & Public Life commissioned the U.S Religious Knowledge Survey to find out how much American's know about faiths around the world.
Thesurprised many in that Atheists and Agnostics scored the highest with an average of 20.9 correct answers. While Jews came in second and Mormons third with 20.5 and 20.3 correct answers respectively, there was a great deal of discussion as to why nonreligious groups scored the highest.
While the survey has finished, the Pew Forum is leaving a sample of the poll open. It offers a fraction of the survey which was given by telephone to just over 3400 people and is available here.