Published January 13, 2015
The Mormon church and evangelical faiths grew during the past decade while more liberal Protestant denominations shrank, according to a new census of U.S. religions conducted by a Roman Catholic research group.
The Church of Jesus Christ of Latter-day Saints grew at the fastest rate, with the Pentecostal denomination Assemblies of God following closely behind, the 2000 Religious Congregations & Membership study found.
The Roman Catholic Church also posted strong growth while its population shifted. More Catholics now live in the West than the traditionally Catholic Midwest, and the Catholic population in the South grew faster than it did in the Northeast.
"That has a lot to do with the growth of the Hispanic population in the United States," said researcher Clifford Grammich, who collected Catholic figures for the study. "How well the church has been holding onto Hispanic Catholics, a study like this can't determine."
The survey is conducted once a decade and was released Tuesday.
The latest version includes Muslims for the first time, finding 1.6 million in the United States. The count was lower by millions than some other surveys, but researchers said the figure was only a tally of those active in mosques, not the total American Muslim population. Estimates of all Muslims vary dramatically from 2 million to 6 million.
The study was conducted by the Glenmary Research Center in Nashville, Tenn., a Catholic research and social service organization that coordinates the study with analysts from several faiths. It's one of just a few religious surveys across denominations.
The 149 participating faiths sent membership estimates to Glenmary, which adjusted the figures to make them comparable. The U.S. Census Bureau does not collect information on religion.
The numbers for each denomination may not be exact, but are close enough to help uncover important trends, said the Rev. Dale Jones, a Church of the Nazarene minister who oversaw the survey.
Jones said one of the most troubling trends was that, in most areas, religious groups failed to increase the percentage of members compared with the total population. This was especially pronounced in the West, where denominations claim the smallest percentage of members.
People there "consider themselves religious, but some will say you don't need to belong to a church to be religious," Jones said.
The study found the Los Angeles metropolitan area was the most diverse urban center, with 106 different denominations reporting members. Illinois was the most diverse state with 120 different faiths.
The evangelical Southern Baptist Convention grew by only 4.9 percent during the last decade, but remained the nation's largest Protestant group, with nearly 20 million members, according to Glenmary. Other surveys put the Southern Baptist figure closer to 16 million.
Roman Catholics remained the largest denomination in the country, growing 16 percent to 62 million believers. The Mormon church grew about 19 percent to 4.2 million members, while the Assemblies of God grew nearly as quickly to 2.6 million.
The Presbyterian Church (U.S.A.) was among moderate and liberal Protestant denominations posting a significant loss, dropping by nearly 12 percent to 3.1 million. Mainline Protestant churches have been losing members for decades.
The study put the Jewish population at 6 million, but Jones said the figure researchers gave Glenmary included Jews who were not members of congregations and therefore was difficult to compare to other participating denominations.
Predominantly black denominations, such as the National Baptist Convention, did not participate in the study, since many lack the resources to count their membership, Jones said.