I am not usually that interested in statistics since I never know quite what to do with them. Here are a few from a mid-2007 on religion in America by the Pew Forum. A few facts of note:
1. Although 78.4% identify themselves as Christians, only 51.3 % consider themselves Protestants.
2. 16.1% are not affiliated with any religous faith–looks like they are one of the fastest growing segments of the population
3. Protestants (and other groups to a lesser extent) have significant internal diversity and fragmentation
I have always thought that our problem was closing the back door and the following conclusion seems to agree.
The survey finds that constant movement characterizes the American religious marketplace, as every major religious group is simultaneously gaining and losing adherents. Those that are growing as a result of religious change are simply gaining new members at a faster rate than they are losing members. Conversely, those that are declining in number because of religious change simply are not attracting enough new members to offset the number of adherents who are leaving those particular faiths.
Here is another link to the same survey in which they asked the following question: When it comes to questions of right and wrong, which of the following do you look to most for guidance? Guess what, religious teachings & beliefs was right up there with Practical experience & common sense, even among evangelicals.