I can recall several instances in my youth and during my mission when people would talk very optimistically about the reported "rapid growth" of the Mormon Church. I am told that just in my life time the Church records have quadrupled. This may be true based on some definitions of what constitutes a Mormon, but of the estimated 14 million members on the roster how many actually consider themselves members of the Church?
For many Mormons the growth rate of the Church represents its veracity. Why would people join the Church in droves if it is not true? Well, the problem with this logic is that it isn't logical. In fact, it is the classic logical fallacy "argumentum ad populum" (argument from popularity). Truth is not a democracy. Besides, many religions boast much higher growth rates, including atheists. Does this mean that they are true? If the Mormon Church's growth rates are on the decline, would this mean it is not true?
According to an article on Richard Packham's site, in 1999 alone the Mormon Church added 306,171 members to their 10,752,986 total membership, while the Seventh-Day Adventists (a much younger religion, mind you) claimed 1,090,848 new members to their 10 million total membership. Mr Packham explains why this is so problematic for the Church:
"Approximately half of all converts each year are outside the United States. Applying that fact to the 273,973 convert baptisms, deducting those who will no longer be active after the first year, the net increase by converts for 2000 was approximately 104,000. Placing that figure against the 87,500 who took the trouble to resign officially, and considering the fact that many who become disenchanted with Mormonism simply walk away without requesting name removal, one must conclude that the net growth of the church - other than by breeding children - is close to zero." [emphasis added]
Until recently I did not know that Mormon higher-ups are offered a salary if they want it, since they usually have to quit their day job when accepting such time-consuming positions. The Church openly criticizes other churches for paying their clergy members, so this puts them in an awkward position, doesn't it? But setting aside any apparent hypocrisy, the real issue is what the Church is currently doing to boost "sales".
In the 80s the Church saw its greatest period of growth, and by the year 2000, despite having twice as many missionaries actively proselytizing, their growth rate dropped to about half. Current figures are difficult to come by, as the Church is very secretive of its membership records (and finances). But it is clear to me at least that they are desperately grasping for anyone willing to buy the snake oil.
I think these declining growth rates are the reason behind the "I'm a Mormon" ad campaign (likely a multi-million dollar endeavor, but good luck finding those figures) and the recent announcement that young Mormon boys and girls can now apply for their missions much earlier (from 19 years old to 18 for boys, and from 21 to 19 for girls). This will likely boost missionary efforts initially, and may even result in additional baptisms, but the problem the Church faces is not that people aren't joining the Church--they are leaving! How will having even more naive and inexperienced missionaries world wide address the issue that so many people leave the Church after their first year of membership (~75%)?
It is difficult to say what would fix the dilemma Mormonism currently faces. If I were interested in finding a remedy (cough, cough), I would suggest they should try being more forthright and honest about their history and odd doctrines. But let's face it, there is a reason they have been so secretive all these years....
Here is the official press release announcing the changes to missionary ages, which Elder Holland says is because "god is hastening his work" (which implies that the Second Coming of Christ is fast approaching, and says nothing about declining membership. Score "1" for being forthright and honest. Oh wait....):
Here is the Mormon Church exploiting compassion towards disabled children to promote their religion:
Well, two can play that game: