Here's an interesting report from
Mormonwiki:
"Sociologist Armand Mauss estimates that 50 percent of LDS converts within the United States stop attending within a year of conversion, and 75 percent of foreign converts fail to attend after a year."[2]
"A closer examination of growth and retention data demonstrates that LDS growth trends have been widely overstated. Annual LDS growth has progressively declined from over 5 percent in the late 1980s to less than 3 percent from 2000 to 2005. Since 1990, LDS missionaries have been challenged to double the number of baptisms, but instead the number of baptisms per missionary has halved.
"While LDS activity rates in the United States are among the highest of any country in the world, less than half of members on the rolls are active. The Encyclopedia of Mormonism reports: 'Canada, the South Pacific, and the United States average between 40 percent and 50 percent [attendance at sacrament meeting].' (Source: Encyclopedia of Mormonism, edited by Daniel H. Ludlow, 1992, 4:1527.)
"Marginal retention of new converts, and especially potential priesthood holders, remains a serious challenge:
"'For the U.S. as a whole, only 59% of baptized males ever receive the Melchizedek Priesthood. In the South Pacific, the figure drops to 35%; in Great Britain, 29%. In Mexico (with almost 850,000 members) the figure is 19%; and in Japan, only 17% of the male members ever make it past the Aaronic Priesthood.' (source: Lowell C. Bennion and Lawrence Young, Dialogue, Spring 1996, p.19.) " [4]
"Many other religions are growing faster than Mormonism, and it is unclear how Mormonism would have a competitive advantage over those religions. Despite increasing the member base and missionary force by 50% over the last decade, the church has been unsuccessful at increasing the number of baptisms by even 1%. When we look at the actual growth rate of the church from 1983 to 2000 there is strong statistical evidence that the slowing growth is due to an underlying trend rather than random fluctuations." -Roger Loomis
"As LDS author and retired CES Director Grant Palmer pointed out in his podcast interview with church member and MormonStories.org founder, John Dehlin [10], the church is 'hemorrhaging' members. Why? As Palmer said, Latter-Day Saints are going on the Internet and discovering, much to their shock, that what the church taught them about Joseph Smith, early church history, and other aspects of Mormonism is far from the truth. According to Palmer's source in Church HQ, about 100,000 members are resigning each year, and Greg Dodge, the man responsible for processing resignations and excommunications has had to double his staff from five people to ten! Two of the 100,000 (approx.) for 2006 include Jerrell Chesney and his wife, president and matron of the Oklahoma City Temple. The Chesneys joined the church in 1970 and served in various church callings over the years. Reportedly, they feel that the church betrayed their faith and abused their trust; many good people with years of experience in the church have felt the same way." (Emphasis added)
"[Rick] Phillips uses recent census data from Australia, Austria, Canada, Chile, Mexico, and New Zealand to attempt an answer to this question. According to the data, the number of self-professed Mormons is between 23-58 percent of the number claimed by the church. (Australia 47.5%, Austria 57.1%, Canada 58.4% (lower outside Alberta), Chile 27.3%, Mexico 23.2%.)"