Congress still mostly Christian, white, male
The percentage of "Nones" in the United States is nearly a quarter of the population, yet just one of the 535 members of the new Congress is religiously unaffiliated.
A report from the Pew Research Center also shows that the 115th Congress remains much more male and white than the rest of the U.S. population.
Only Arizona Democratic Rep. Kyrsten Sinema admits to being "unaffiliated," which Pew defines as people who are atheist, agnostic or who describe their religion as "nothing in particular." That means only 0.2 percent of Congress is unaffiliated, compared with 23 percent of U.S. adults. That unaffiliated group, also called the Nones, is the fastest-growing "religious" group in America, according to a previous Pew study.
More than 90 percent of members of Congress are Christian, compared with 71 percent of U.S. adults.
Part of the reason for this huge gap is that Nones tend to be younger, while a congressional members' average age was 57 in the 114th Congress. Since the Nones are among the youngest of all "religious" groups, the expectation is that as they age, more of them will be elected to Congress and will start to make up the dramatic difference that currently exists.
Also, because Nones are younger, they tend to vote at lower rates than older Americans, so they may be underrepresented partly for that reason, as well.
And finally, not being religiously affiliated also means there is not a concerted voting bloc that is politically motivated.
"They may be unaffiliated; they may be atheist; they may be agnostic, but they're not part of some club," Margie Omero, a Democratic strategist at Purple Strategies, told National Public Radio in 2015. "You could certainly argue that evangelicals are not monolithic in terms of their policy beliefs, but there's no denying that there's more of an organization around organized religion than there is around disorganized atheism."