More than 13 million atheists and agnostics and nearly 33 million claim no particular affiliation. About 20 percent of U.S. adults say they had no religious affiliation, an increase from two decades ago when about 8 percent of people were deemed so-called “nones,” according to a new study released Tuesday by the Pew Research Center’s Forum on Religion and Public Life. The group will be the subject of an upcoming PBS miniseries this month.

“But despite their nickname, the “nones” are far from godless. Many pray, believe in God and have regular spiritual routines,” The Washington Post’s religion reporter Michelle Boorstein wrote Tuesday.