Chicago • The vast majority of Americans may be Christians, but fewer than half join a congregation and that trend, warns a religion researcher, should concern church leaders.
"In some ways, our chickens have come home to roost," said Dale Jones, a research director with the Church of the Nazarene who worked on the newly released U.S. Religion Census. "Churches have talked about needing to have a personal relationship with Jesus Christ what you hear is, 'I need a relationship, I need to be born again,' but not, 'I need to be involved in a congregation.' Guess what? That's where we are."
The once-a-decade census, unveiled Tuesday, found that while upward of 80 percent of Americans claim to be Christians, only about 49 percent are affiliated with a congregation.
While other studies examine total membership, beliefs or worship attendance, this one counts the actual number of people who are affiliated with U.S. congregations or, as Jones put it, the people who are "involved enough to the point where they know to count you."
And the latest numbers show that mainline Protestants and Catholics, who dominated the 20th century, are losing ground literally to the rapid rise of Mormons and Muslims.
This census tracks Americans' religious affiliations down to the county level from the largest (Los Angeles County, where Mormons grew 55 percent while Catholics shrank by 7 percent) to the smallest (Loving County, Texas, which is home to 80 people and one nondenominational evangelical church).
Mormons were the fastest-growing Christian denomination in more than half the U.S. states. Muslims came in second, with growth of 1 million adherents in 197 new counties, to a total of more than 2.6 million.
Overall, non-Christian groups grew by 32 percent during the past decade.
"Mosques have multiplied at a growth rate of about 50 percent," said Dale Jones, a researcher with the Church of the Nazarene who worked on the study. "They have more religious centers, and simply moving into the suburbs puts you closer to where a lot of your folks are living."
The study identified nearly 350,000 religious congregations in the United States from Albanian Orthodox to Zoroastrian. Those churches, temples and mosques are the spiritual home for 150.6 million Americans, and researchers say they were able to capture 90 percent of all U.S. congregations.
The research relies mainly on self-reported data from churches and denominations. Some, including several historically black churches, failed to submit information on new numbers. Researchers were able to reach only a third of U.S. mosques and had to estimate the rest.
Researchers did not track growing numbers of secular or religiously unaffiliated Americans estimated at about 16 percent of the country, according to other studies because they do not belong to a congregation.
The study also tracked the growth of nondenominational and independent evangelical churches, which combined represent the nation's third-largest Christian group, at about 12.2 million adherents across 35,000 congregations.
Catholics, while losing about 5 percent of adherents in the past years, nonetheless remain the nation's largest religious group, at about 59 million. The Southern Baptist Convention came in second, at 19.8 million, but its 50,816 congregations made it the group with the most churches.
The rapid growth among American Muslims likely has several explanations, researchers said: growth in the suburbs, an increased willingness by U.S. Muslims to stand and be counted and more mosques being built to serve more worshippers.
Imam Muhammad Musri, president of the Islamic Society of Central Florida, saw growth explode by a whopping 473 percent in and around Orlando's Orange County, according to the census, and he thinks the growth is actually double the 10,000 new Muslims reported.
He said Muslim growth has been fueled by a wave of post-9/11 converts, American-born children of immigrants having kids of their own, and jobs in the booming medical industry. In central Florida, he said, Muslims are just following everyone else in search of "better weather, cheaper prices, cheaper homes."
"I doubt in the next decade we will grow as much," he said. "It's like a new product when it's first introduced, there's lots of interest. But now we're more of a known quantity and we're not going to be opening as many new mosques as we were in the last decade."