How did Mormons grow so fast? They changed how they counted

If you suspected the newly released U.S. Religion Census overstated the Mormons' growth rate, you were right. That’s because, this time around, the Utah-based Church of Jesus Christ of Latter-day Saints changed the way it reported its membership to the researchers.

Its report pegged U.S. Mormon growth at 45.5 percent, jumping from 4.2 million in 2000 to 6.1 million in 2010. The 2000 figure, however, was much lower than the 5.2 million listed in the LDS church’s own almanac for that year. If researchers had been given that figure, the percentage of growth would have been considerably smaller, closer to 18 percent. ...