Despite the apparent rise in people with no religion, the overall percentage of non-believers is expected to decline as a share of the world's population, according to a new survey from the Pew Research Center

By 2050, the number of people who identify as atheist, agnostic, or who say they have no particular religion will grow by 100 million, for a total of 1.2 billion people. But the percentage of believers will vastly outpace that growth, expanding by more than 2 billion over the same span of time. As a result, the percentage of non-believers, while growing in real terms, will decrease from 16 to 13 percent of the world's population by 2050.

The study, which classifies non-believers as religions "nones," points out that nones tend to be older, meaning they will die sooner, and have fewer children than people who are associated with religion. In addition, the 10 countries with the largest unaffiliated populations in the world as of 2010 are all expected to decline as a share of the world’s population by 2050. 

While some have speculated that religious faith decreases as societies become more affluent, there is scant evidence for this trend beyond nations in Western Europe. No such phenomenon occurs in Muslim-majority countries, and in Hindu-majority India, "religious affiliation is still nearly universal despite rapid economic and social change."

China also represents an interesting case study since it does not keep reliable data on religious affiliation, though many believe Christianity is on the rise in the communist country. If that does prove true, the ratio of "nones" could decrease even more by 2050. 

Demographic studies like the one released by Pew are essential tools in understanding future trends on a global scale. In his Big Think interview, Paul Taylor, the executive vice president of the Pew Research Center, discusses what makes Millennials a "very distinctive" generation:

Read more at Demographic Research.