The typical American underestimates how many Protestants there are in the U.S., and vastly overestimates the number of religious minorities such as Mormons, Muslims, and atheist/agnostics, according to a new study.
Grey Matter Research and Consulting asked 747 U.S. adults to guess what proportion of the American population belongs to each of eight major religious groups: Protestant, Catholic, Jewish, Mormon, Muslim, atheist/agnostic, believe in God or a higher power but have no particular religious preference, and any other religious group. The average response was that 24 percent of Americans are Catholic, 20 percent are Protestant, 19 percent are unaffiliated, 8 percent are Jewish, 9 percent are atheist or agnostic, 7 percent are Muslim, 7 percent are Mormon and 5 percent identify with all other religious groups.
Respondents were correct on Catholics — 24 percent of the country is Catholic. But according to the 2008 U.S. Religious Landscape Survey from the Pew Forum on Religion & Public Life, 51 percent are Protestant, 12 percent are unaffiliated, 2 percent are Jewish, 4 percent are Atheist/Agnostic, less than 1 percent are Muslim, 2 percent are Mormon and 4 percent identify with all other religious groups.