Pew Research declared:
{{cquote|These projections, which take into account demographic factors such as fertility, age composition and life expectancy, forecast that people with no religion will make up about 13% of the world’s population in 2050, down from roughly 16% as of 2010.
This is largely attributable to the fact that religious “nones” are, on average, older and have fewer children than people who are affiliated with a religion. In 2010, for instance, 28% of people who belong to any of the world’s religions were younger than 15 years old, compared with just 19% of the unaffiliated. And adherents of religions are estimated to give birth to an average of 2.6 children per woman, compared with an average of 1.7 children among the unaffiliated.<ref>[http://www.pewresearch.org/fact-tank/2015/04/03/why-people-with-no-religion-are-projected-to-decline-as-a-share-of-the-worlds-population/ Why people with no religion are projected to decline as a share of the world’s population], Pew Research. April 3, 2015</ref>}}