This is the annual Gallup Poll on the American religious landscape. It was done throughout 2017 of a random national sample of 126,965 adults, and has a margin of error of only 1 point. The top chart shows the 2017 religious landscape compared to the 2016 one.

Note that only two groups showed an increase in 2017 over 2016 -- the other nonchristian groups and the nonreligious. Mormons, Jews, and Muslims remained steady. Both Protestants and Catholics showed a decrease in membership.

I found the chart below very interesting. They divided respondents into three groups -- the highly religious, the moderately religious, and the nonreligious. Among the general public and among whites, the support grew as religiosity grew. Among nonwhites, religiosity did not matter (with very little support for Trump among all three groups).

That amazes me. Support for Trump (the most nonreligious president we've had, especially considering his actions and stated values) is highest among the highly religious. How can they justify that?