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 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."

In Hawai'i, the Church of Jesus Christ of Latter-day Saints grew by 11 percent and reported a membership of 42,758.

The Catholic Church remains the largest denomination in Hawai'i with 240,813 members, an increase of 3.5 percent.

Buddhists, the second largest faith organization in Hawai'i with an estimated 100,000 members, did not report their total numbers.

The latest version of the survey 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.

The 149 participating faiths sent membership estimates to Glenmary, which adjusted the figures to make them comparable.

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.

The evangelical Southern Baptist Convention grew by only 4.9 percent during the past decade, but remained the nation's largest Protestant group, with nearly 20 million members, according to Glenmary.

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.

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.

Advertiser staff writer Mary Kaye Ritz contributed to this report.