This Christmas season, 78% of American adults identify with some form of Christian religion. Less than 2% are Jewish, less than 1% are Muslim, and 15% do not have a religious identity. This means that 95% of all Americans who have a religious identity are Christians.
These results are based on a compilation of 327,244 interviews conducted as part of Gallup Daily tracking from January-November 2011. The detailed breakdown shows that about a third of American Christians are Catholics, while two-thirds identify as Protestants or some other non-Catholic Christian religion. All in all, 82.5% of Americans have some form of religious identity.
Gallup's methods of measuring religious identity have changed over the decades, but one major trend that is clear from Gallup's and other organizations' surveys is the increase in the percentage of Americans who do not have a formal religious identity. Some 60 years ago, in 1951, for example, just 1% of Americans in Gallup surveys said they didn't have a religious identity. At that time, Gallup classified 68% of Americans as identifying with a non-Catholic Christian faith, and 24% who were Catholic.
Separate Gallup questioning earlier this year shows that 92% of Americans say they believe in God. This suggests that the lack of a religious identity is not in and of itself a sign of the total absence of religiosity.