Another challenge for those believers: Religion may become extinct in nine nations, study says/http://www.bbc.com/news/science-environment-12811197

The research team apply their nonlinear dynamics model, adjusting parameters for the relative social and utilitarian merits of membership of the "non-religious" category.

"For example in languages, there can be greater utility or status in speaking Spanish instead of [the dying language] Quechuan in Peru, and similarly there's some kind of status or utility in being a member of a religion or not."