Forty years ago, they were 81 percent. As a share of the population, they’ve been cut almost in half. That’s the key takeaway from the always fascinating PRRI religious survey. Eyeball the first pie chart at the link and you’ll see that non-Christian religions are still a tiny share of the overall population.
It’s not other faiths that are shrinking the percentage of white Christians, it’s a combination of racial change and growing secularism. A lot of white Christians have drifted into the “unaffiliated” category, which now accounts for nearly a quarter of all Americans.