Why do you doubt that 45% (roughly) of the people attend chuch?
Why do I doubt 45% of the American electorate goes to church on a weekly basis? For one, the ratio of churches to population. I don't think it would even be physically possible. If you exclude non-christians from the population, your statistics would imply that around 50% of all people who identify as some form of Christian go to church on a weekly basis. Again, I don't think so.