what percentage of Americans go to church regulalry overall? 20-30%?
This is an interesting question, in more ways than one. First of all, as you'd probably expect, attendance varies quite a bit by state. I'm proud to say that the state I consider to be my adopted home state, Vermont, has the lowest attendance, as well as the highest number of atheists.http://www.religionfacts.com/religion_statistics/church_attendance_by_state.htm
There are reasons, however, to doubt the numbers given in surveys such as the one above. This article explains why:http://www.religion-online.org/showarticle.asp?title=237
Briefly, there are a lot of people here who don't go to church regularly but say they do because they feel like they have to due to cultural pressure. It's somewhat like going to the dentist. People who don't brush and/or floss often enough frequently overreport how diligent they are about their oral hygiene because they don't want to admit the truth.
In parts of the South, especially, pressure to attend church is especially strong, even in some ways that might not occur to most people. When two people are introduced to each other for the first time, for example, one of the first introductory questions often presented, along with "where are you from?", "where do you work?", and so on, is "what church do you go to?" If you reply that you don't go to church, people will, at the least, look at you a little oddly and wonder whether there's something wrong with you. And openly declaring atheism in such areas will, indeed, subject you to various forms of discrimination.
In other parts of the country, atheism is no big deal. I live in the Metro DC area and have never had any problems with being an open atheist. I did get some static about it when I was living in Hawaii, but that was mostly when I was in school and can likely be chalked up to the fact that children are often cruel to each other. Ditto when I was living in central Florida.
Now, if you'll excuse me, I have to go floss.