When the new 114th Congress is sworn in tomorrow, Republicans will control both the House and the Senate for the first time since 2006. In many ways, Congress doesn't look like the rest of the United States: Members are richer, more educated, more white and more likely to be men. This round of senators and representatives is no different. One underrepresented group, however, is often overlooked: the religiously unaffiliated.

Although Congress resembles the U.S. population for the most part in terms of religious populations, declaring a religion seems to be one thing required of politicians seeking office. Only one member, Rep. Kyrsten Sinema, D-Ariz., identifies as religiously unaffiliated.

The greatest difference between Congress and the U.S. is the religiously unaffiliated, who are underrepresented by 20 percentage points. While 20 percent of Americans identify as religiously unaffiliated, the one member of Congress identifying that way means 0.2 percent of Congress is religiously unaffiliated.

Christians make up both the majority of Congress and the majority of the U.S., but are overrepresented – 91.8 in Congress compared with 73 percent of American adults, according to Pew Research Center. Within Christian denominations, most are overrepresented (Protestant in general and Catholicism). Some of the smaller denominations are unrepresented: Baptist and Pentecostal, for example. Other than Jews, which are overrepresented by 3 percent compared to the general U.S. population, religious minorities such as Buddhists, Muslims and Unitarian Universalists are in Congress at about the same rates as the U.S. population.

