This recent article from anonhq.com has been widely shared on Facebook.
A recent global survey conducted by National Geographic shows that the worlds fastest growing religion is not Islam or Christianity, but no religion at all – atheism.
However, the cited article from National Geographic makes a much weaker claim.
The religiously unaffiliated, called "nones," are growing significantly. They’re the second largest religious group in North America and most of Europe. In the United States, nones make up almost a quarter of the population. In the past decade, U.S. nones have overtaken Catholics, mainline protestants, and all followers of non-Christian faiths.
National Geographic makes a firmer distinction between "nones" and atheists.
Within the ranks of the unaffiliated, divisions run deep. Some are avowed atheists. Others are agnostic. And many more simply don’t care to state a preference.
Are the stronger claims that the number of religiously unaffiliated people is growing faster (in absolute terms) than any religion?