There's a good article about certain innacuracies in interpreting the recent "US Religious Landscape Survey", at CNA.
I noticed, when it was released, that everyone with an axe to grind, especially in cyberspace, rushed to use the survey to prove their own particular versions of gloom and doom. Actually taking a close look at the survey, in context, presents a different story.
For example, Mark Gray, of CARA, points out that, while the Church lost more members than any denomination “it's also the biggest religion and when you translate the discussion in to proportions you can see the Catholic Church is doing quite well comparatively. It keeps more of its young faithful than any Protestant denomination.”
68% of those who are raised Catholic, stay Catholic. Compare that with the rates of 60% for Baptists, 59% for Lutherans, 47% for Methodists and Pentecostals, 45% for Episcopalians, and 40% for Presbyterians. Contrary to hype, there's no mass exodus from the Church.
Furthermore, there's been no sudden loss, but a steady rate over the years. 54% of those who have left the Church did so before 1988. That rather puts a crimp in the blame game.
The simple truth is that the Church is steadily growing.