The Religiously Unaffiliated now rank as the world's third largest religious group, after Christians and Muslims. According to a report recently released by the Pew Research Center, this means that 1.1 billion people, or 16% of the world's population, are atheists, agnostics, or people who do not identify with any particular religion in surveys.
Numbering 858,580,000, the majority (76%) of the religiously unaffiliated live in Asia and the Pacific. The rest are in Europe (12%), North America (5%), Latin America and the Caribbean (4%), sub-Saharan Africa (2%) and the Middle East and North Africa (less than 1%). China has the largest unaffiliated population—half of its citizens do not lay claim to a religion. After China's lion's share of 62.2% of the world's unaffiliated population, Japan contributes 6.4% and the U.S. follows with 4.5%.
In terms of age of adherents, the youngest world religion is Islam, with a median age of 23. Hindus have a median age of 26. At 30, Christians are in the middle of the age spectrum, followed by folk religionists (33), the unaffiliated (34), Buddhists (34), and Jews (36).The median age of the world's population is 28.