America at 300 million

34% are Evangelical Protestant
22% are Mainline Protestant
21% are Roman Catholic
11% are unaffiliated
5% are Black Protestant
2.5% are Jewish
The remaining follow Islam or Buddhism
According to the study, 5% are atheist.
But then no, the numbers don’t add up: 61% Protestant and 21% Roman Catholic equals 82%, when the religious with no affiliation are added we have 93%, and then by adding Jewish we come to 95.5%. Obviously these numbers are rounded, but it only leaves room for 4.5% of the population that are atheist, Buddhist, or follow Islam.