Their numbers have increased dramatically over the past two decades, according to the study released Tuesday. About 19.6 percent of Americans say they are “nothing in particular,” agnostic or atheist, up from about 8 percent in 1990. One-third of adults under 30 say the same. Pew offered people a list of more than a dozen possible affiliations, including “Protestant,” “Catholic,” “something else” and “nothing in particular.”
For the first time, Pew also reported that the number of Americans identifying themselves as Protestant dipped below half, at 48 percent. But the United States is still very traditional when it comes to religion, with 79 percent of Americans identifying with an established faith group.
Experts have been tracking unaffiliated Americans since their numbers began rising, but new studies are adding details to the portrait.
Members can be found in all educational and income groups, but they skew heavily in one direction politically: 68 percent lean toward the Democratic Party. That makes the “nones,” at 24 percent, the largest Democratic faith constituency, with black Protestants at 16 percent and white mainline Protestants at 14 percent.
By comparison, white evangelicals make up 34 percent of the Republican base.
The study presents a stark map of how political and religious polarization have merged in recent decades. Congregations used to be a blend of political affiliations, but that’s generally not the case anymore. Sociologists have shown that Americans are more likely to pick their place of worship by their politics, not vice versa.
Some said the study and its data on younger generations forecast more polarization.
“We think it’s mostly a reaction to the religious right,” said Harvard political scientist Robert Putnam, who has written at length about the decline in religious affiliation. “The best predictor of which people have moved into this category over the last 20 years is how they feel about religion and politics” aligning, particularly conservative politics and opposition to gay civil rights.
Americans have been fleeing institutions in general, Putnam wrote in his bestselling book “Bowling Alone,” about the decline of such institutions as hobby clubs and alumni associations. The culture is also more secular, with prayer in schools and the closing of businesses on Sundays fading along with traditional religious norms on marriage and sex.
For the presidential campaigns, the data reflect a simple fact on the ground. Three-quarters of unaffiliated voters voted for Barack Obama in 2008. Today, the unaffiliated break like this: 65 percent for Obama, 27 percent for Republican nominee Mitt Romney.