From the 2017 PRRI study, "America’s Changing Religious Identity," by Daniel Cox and Robert P. Jones, Ph.D.—excerpts below:
The National Decline in White Christian Identity
Demographically, the U.S. historically has been an overwhelmingly white Christian country, with white Protestants alone constituting a clear cultural majority. In 1976, roughly eight in ten (81%) Americans identified as white and identified with a Christian denomination. At that time, a majority (55%) of Americans were white Protestants.
Much of the decline has occurred in the last few decades. As recently as 1996, white Christians still made up nearly two-thirds (65%) of the public. By 2006, that number dropped to 54%, but white Christians still constituted a majority.8 But over the last decade, the proportion of white Christians in the U.S. has slipped below majority. Today, only 43% of Americans identify as white and Christian—and only 30% as white and Protestant.
The Growth of Nonwhite Christians
Increasing Racial and Ethnic Diversity Among Protestants
Today, three in ten (30%) Americans are white Protestant. This is a considerable decline over the past couple of decades; in 1991, white Protestants represented half (50%) the public. 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. In 1991, 83% of all Protestants were white, compared to two-thirds (67%) today. One-third (33%) of all Protestants are now nonwhite.
However, the degree of racial and ethnic diversity among Protestants varies considerably between denominational families. More than nine in ten Lutherans (92%) and roughly eight in ten Methodists (83%), Presbyterians (83%), and Episcopalians (80%) are white, non-Hispanic. In contrast, fewer than six in ten (58%) Baptists are white, and a sizeable share of members are black (30%) or Hispanic (5%). Similarly, only half (50%) of Pentecostals are white, while one-quarter (25%) are Hispanic, and 17% are black. Protestants who belong to non-denominational Protestant churches are also somewhat diverse: Two-thirds (67%) are white, 13% are black, and 10% are Hispanic.
Rise of the Religiously Unaffiliated
The religiously unaffiliated—those who identify as “atheist,” “agnostic,” or “nothing in particular”—now account for nearly one-quarter (24%) of Americans. Since the early 1990s, this group has roughly tripled in size.