Look at the countries going backwards: USA , Russia, Japan. These are countries that were superpowers but are now on the way down. This fits with the theory that god appeals in times when things are going worse and it appears there is not much you can do about it, so you gamble on an invisible man. It is much the same as the poor trusting in lotteries.

There is also a majority effect. It is dangerous to express religious beliefs different from your neighbours. So I think you will have atheism underreported in a theistic country and belief underreported in an atheistic country.

If numbers were taken by age group, you could project future rates, even if no attitudes changed. I know the young are much more open to equality for gay people, which is a pretty strong measure of rejection of Christianity.

The key to change is winning over the young. That is why the Christians work so hard to isolate children from any other ideas. Teens are naturally rebellious and open to new ideas. That is where we should focus.

[Plug for own book removed by moderators]