Abstract

The religious profile of the world is rapidly changing, driven primarily by differences in fertility rates and the size of youth populations among the world’s major religions, as well as by people switching faiths. Over the next four decades, Christians will remain the largest religious group, but Islam will grow faster than any other major religion.

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Pew Research Center

02-04-2015

http://www.pewforum.org/2015/04/02/religious-projections-2010-2050/