Last post I looked at some statistics on church attendance, which has been declining in recent years in many countries. This is just a brief aside to reference a post on the Christian CADRE blog suggesting that while churches may be losing numbers, these people are not going over to atheism, at least not in the US.
It seems that people who leave churches either keep on following Jesus, probably more seriously than they did before, or else they hold to some religious beliefs, probably in a less formal way.
On The Arda there is an article by Mark Chaves that also discusses this subject. He thinks that over five decades, there has been a decline in belief in God even though it has stabilised twenty years ago.