These are quotes from the following article. I think they are quite key. All things considered I don't think the dubs are doing to bad after all
Between 1990 and 2001 the Church claimed they had 5.3 million members, but in the City University of New York (CUNY) report only 2.8 million Americans identified themselves as Mormons. In an interesting comparison more people identified themselves as Jehovah Witnesses than their church claimed to have on the roles
According to Cumorah.com the Church’s activity rate is dismal at best. They reported that only “22% of U.S. members born to active LDS families remain active lifelong, whereas 44% returned after inactivity of at least a year or more”. Children born into inactive families remained inactive themselves if they even affiliated themselves with the Church..