Old time religion? Median age of U.S. Latter-day Saints is rising. Muslims make up the youngest religious group.

Sweeping survey shows a dip in the number of “nones” and an increasingly homogeneous Republican Party, dominated by white Christians.

As a group, members of The Church of Jesus Christ of Latter-day Saints, who make up 1% of the U.S. population and 2% of white Christians, are neither the oldest nor the youngest religious contingent in the country.

The median age for Latter-day Saints is 47 (matching the nation’s overall median but up from 44 seven years ago), while the oldest believers are white evangelical Protestants, with a median age of 56, and the youngest are Muslims, with a median age of 33.

These are among the findings of PRRI’s 2020 Census of American Religion, which provides, according to a Thursday release, “unprecedented county-level data on religious identity and diversity in the United States.”

The survey is based on interviews “with more than 500,000 respondents between 2013 and 2020,” the release said, and “reveals the shifting dynamics of American religious affiliation across geography, race and ethnicity, age, and political affiliation over the last decade.”

Other findings include:

• The highest concentration of Latter-day Saints in counties with more than 10,000 residents is — no surprise — Utah County (72%), home to the faith’s premier school, Brigham Young University in Provo. The second highest was Madison County, Idaho (68%), which includes Rexburg and BYU-Idaho.

• Some 40% of Latter-day Saints have degrees from a four-year college — fewer than Hindus (67%), Unitarian Universalists (59%), Jewish Americans (58%), Orthodox Christians (48%), and white Catholics (42%).

• The proportion of religiously unaffiliated Americans — the so-called nones — hit a high point of “26% in 2018 but has since slightly declined, to 23% in 2020.” The biggest group to step away from religious associations was young people, the survey said. “In 1986, only 10% of those ages 18–29 identified as religiously unaffiliated. In 2016, that number had increased to 38%, and declined slightly in 2020, to 36%.”

• More than 4 in 10 Americans (44%) identify as “white Christian,” with the majority being “evangelical Protestants (14%), white mainline (non-evangelical) Protestants (16%), or white Catholics (12%),” plus smaller percentages who identify as Latter-day Saints, Jehovah’s Witnesses and Orthodox Christians.

• The proportion of white Christians on the religious landscape “hit a low point in 2018, at 42%,” the survey said, “and rebounded slightly in 2019 and 2020, to 44%.”

• On the issue of politics, the survey reaffirmed that most Latter-day Saints identify as Republicans (39%) or independents (42%). Then-President Donald Trump carried Utah with 58% of the vote in 2020. Only 16% of Latter-day Saints label themselves Democrats.

• Christians make up the majority of both parties — 83% of Republicans and 69% of Democrats. “The biggest difference in the religious makeup of self-identified Republicans and Democrats is the proportion of white Christians compared to Christians of color,” the survey said. “Nearly 7 in 10 Republicans (68%) identify as white and Christian, compared to less than 4 in 10 Democrats (39%).”

The survey noted that “Black Protestants, most heavily concentrated in the South and the Southeast, overwhelmingly identify with the Democratic Party” — 65% — while only 7% identify as Republicans, and 26% identify as independents.”

“Analysis of the religious identities of the two political parties reveals an increasingly homogeneous Republican Party, comprised overwhelmingly of white Christians, even as the country continues to become more diverse,” Robert P. Jones, CEO and founder of PRRI, said in the release. “In terms of racial and religious diversity, self-identified Democrats look like 30-year-old America, whereas Republicans look like 70-year-old America.”

The survey’s overall margin of error is plus or minus 0.5 percentage points. The total sample size in Utah was 554.