"Not only have white Protestants experienced a substantial decline as a proportion of the general population, they also represent a shrinking proportion of all Protestants," the report said.
The percent of white Christians has dropped from 81 percent of the U.S. population (1976) to 43 percent (2016), while the religiously unaffiliated has grown from 7 percent to 24 percent over the same period.
These were two key trends revealed in a Public Religion Research Institute (PRRI) report released on Sept. 6.
"Much of the decline has occurred in the last few decades," the report noted. "As recently as 1996, white Christians still made up nearly two-thirds (65 percent) of the public. By 2006, that number dropped to 54 percent, but white Christians still constituted a majority. But over the last decade, the proportion of white Christians in the U.S. has slipped below majority."
White evangelical Protestants currently make up 17 percent of the U.S. population, followed by white mainline Protestants (13 percent), white Catholics (11 percent), black Protestants (8 percent), and Hispanic Catholics (7 percent).
"Not only have white Protestants experienced a substantial decline as a proportion of the general population, they also represent a shrinking proportion of all Protestants," PRRI explained. "In 1991, 83 percent of all Protestants were white, compared to two-thirds (67 percent) today. One-third (33 percent) of all Protestants are now nonwhite."
Baptists continue to represent that largest percentage of the U.S. Protestant group (31.9), followed by nondenominational (17.1), Methodist (10.1), Pentecostal (9.7) and Lutheran (7.7).
Non-Christian traditions have seen growth but still remain a small minority. "Muslims, Buddhists and Hindus are each roughly 1 percent of the population. Jewish Americans account for 2 percent of the public," the report stated.
The trends are most visible along generational lines.
The religiously unaffiliated represent 38 percent of 18- to 29-year-olds, compared to 26 percent aged 30-49, 18 percent aged 50-65, and 12 percent aged 65-plus.
Among white evangelical Protestants, 26 percent of adults 65 and older identify with this group, compared to 21 percent aged 50-64, 14 percent aged 30-49 and 8 percent aged 18-29.
While white mainline Protestants and white Catholics both followed the pattern of white evangelical Protestants, Hispanic Catholics did not.
Nine percent of 18- to 29-year-olds identify as Hispanic Catholics and 10 percent of those aged 30-49 did so, compared to 6 percent (50-64) and 4 percent (65 plus).
While those affiliating with Christian traditions are more pronounced among older generations, non-Christian tradition affiliation is seeing growth among the younger generations.
PRRI found that "at least one-third of Muslims (42 percent), Hindus (36 percent) and Buddhists (35 percent) are under the age of 30."
The full report is available here.