The declining cohort of the religious and growing cohort of atheists appear significantly dissimilar.
Religious folk believe in magic and goods merely because they have been indoctrinated with faith and have faith only because they have been indoctrinated to believe - in spite of the total and absolute absence of any evidence of the existence of any of the millions of gods, goddesses and god-men.
Atheists do not believe in magic and any of the millions of gods because there is no reason for, or evidence of; the existence of any of those millions of gods, goddesses and god-men.

Atheists do not say "there is no god". We observe that there is no evidence of any of the millions of gods that appear in human authored fiction but never in the real world or universe.