The Church of Jesus Christ of Latter-day Saints was the fastest-growing Christian church in America from 2000-10, but it didn't grow as fast as reported Tuesday.
The church said Thursday that its American membership grew 18 percent during the first decade of the 21st century, not 45.5 percent as reported Tuesday in the 2010 decennial U.S. Religion Census released by the Association of Statisticians of American Religious Bodies.
The census showed the church's membership to have jumped from 4,224,026 in 2000 to 6,144,582 in 2010, or 45.5 percent. However, the church's full membership in 2000 was 5,208,827.
LDS Church spokesman Scott Trotter said the church previously used an understated number when reporting to the census, but decided this year to report full membership numbers. The 6.1 million figure in 2010 better reflects the church's total membership.
“Total church membership numbers are derived from those individuals who have been baptized or born into The Church of Jesus Christ of Latter-day Saints," Trotter said Wednesday. They are neither projections nor estimates. "In past years, numbers reported to the (census) were understated. They left out numbers of members who, although baptized, were not currently associated with a specific congregation. This year we included total membership numbers to more accurately reflect all of those found on church records.”
Dale Jones, a researcher on the religion census, said the discrepancy just wasn't caught in time before they compiled the numbers.
"Those of us who collected the data and put it out this week simply didn't catch the fact the (LDS Church) methodology for calculating adherents had been changed since the last analysis," Jones said. "I would point out that the new methodology is really more consistent with the way other groups like Catholics and Protestants are already reporting the data. So I think it's a good move; I just wish we had realized it earlier."
Despite the reporting discrepancy, 18 percent growth was still the highest among Christian sects in America. The Assemblies of God grew 14.9 percent. Catholic adherents have dropped 5 percent in the past decade, while Mainline Protestants have seen a decline of 12.8 percent. Evangelical Protestants have seen a small 1.7 percent growth among adherents.
"It's roughly half the gains we expected early, but the gains are still very dramatic for the Latter-day Saints," Jones said.