The number of Americans who say they are atheist or agnostic, or choose not to identify with a religious tradition has increased modestly over the past two decades, with Pew surveys since the beginning of 2006, finding that 12% of U.S. adults identify themselves as secular or unaffiliated with a religious tradition; that compares with 8% in the Pew values survey in 1987. This change appears to be generational in nature, with new cohorts coming of age with lower levels of commitment to a religious tradition. Among respondents born before the baby boom (that is, prior to 1946), only about 5% are secular or unaffiliated compared with more than double that number among Baby Boomers (11%). The most secular Americans are those 30 and younger — sometimes called “Generation Y” — 19% of whom do not identify with a religious tradition. Pew surveys taken over the past 20 years show that, within each age cohort, the size of the secular group has remained constant over time indicating that people have not become less secular as they have aged. For example, 14% of members of “Generation X” (born 1965-1976) did not identify with a religious tradition in 1997, about the same as in 2007. Democrats and independents are less likely than Republicans to identify with a particular religious tradition, and the gap has widened over the past two decades. Currently, 5% of Republicans say they are atheist, agnostic, or decline to state a religious preference, which is the same percentage that did so in 1987. But the number of Democrats in this category is now 11%, up from 7% in 1987; currently 17% of independents are classified as secular, an increase from 9% in 1987. Read More

Russell Heimlich  is a former web developer at Pew Research Center.