Study: 'No Affiliation' Is Third-Largest Religious Group WorldwideA growing trend emerged from a comprehensive 2010 study of worldwide religions: roughly one-in-six (1.1 billion, 16 percent) of the world’s population claims no religious affiliation.
Study: One-Third Of Adults Under 30 Have No Religious AffiliationOne-fifth of American adults have no religious affiliation, and this number is growing rapidly.