Mormons remain among the youngest, most fertile and politically conservative of U.S. religious adherents. And, while other faith groups have suffered sharp declines in membership, the LDS percentage of the nation’s population seems to be holding steady.

Those are among the conclusions noted in a massive study, “America’s Changing Religious Identity,” released Wednesday by the Public Religion Research Institute.

The survey polled more than 100,000 Americans from all 50 states, including 1,740 members of The Church of Jesus Christ of Latter-day Saints.

It found that 1.9 percent of Americans identify as Mormon, identical to findings from a 2011 study of Latter-day Saints. Fewer than half of Mormons (41 percent) are 50 or older, and nearly a quarter (23 percent) are under age 30, making them the youngest Christian faith group. Muslims top the overall list, with 42 percent under age 30.

A little more than a third of Mormons (34 percent) have a high school education or less, while 32 percent have at least four-year college degrees.

Christians from racial and ethnic minority groups tend to have the lowest household incomes, the survey showed, with nearly half of Hispanic Catholics (49 percent) earning less than $30,000 a year. Barely a quarter of Mormons (26 percent)report household incomes in that range.

Many of the conclusions match what LDS researcher Jana Riess has found with her study of Mormon millennials.

“This is great,” the Cincinnati-based writer said Wednesday. “In general, the statistics were consistent with our findings.”

On some topics, such as education and socioeconomic levels, she said, “they were almost identical.”

Riess did question the finding that the LDS Church’s percentage of the population is the same — about 2 percent — as it has been in the past.

The survey asserts that “Mormonism has so far been immune to the current decline of Christianity in America,” she said. “As much as I would love to believe that Mormonism has nothing to fear, that is not what some of the other studies have been finding.”

Riess would want to “know more about how they’re coming up with that,” she said. “Are they seeing generational change in the way we are?”

On the question of fertility, the survey noted that Mormons have “by far the largest families” of any U.S. faith group. Some 42 percent of LDS parents say they have at least three children in their homes under age 18.

The nation’s fertility rate is declining, Riess explained, but that is similarly true of the LDS rate — young Mormons have smaller families than their parents and grandparents did.

Riess also was intrigued by the poll’s political results.

The survey showed that four in 10 Mormons (44 percent) identify with the GOP, while 57 percent view themselves as “politically conservative.”

Identification with the Republican Party was “lower in our study than it had been in the past, and this was even lower than ours,” Riess said. “Some kind of shift is happening where Mormons are becoming interested in identifying as political independents.”

Only 15 percent of Latter-day Saints call themselves liberal.

Other findings:

• More than three-quarters of U.S. Mormons (83 percent) are non-Hispanic whites.

• Mormons comprise 51 percent of Utahns, and 61 percent of Utahns are white Christians.

• While women make up larger majorities of most American religious groups, in Mormonism, the genders are more evenly divided — 48 percent male, 52 percent female.

• More than two-thirds of the nation’s Mormons (68 percent) are married.