Americans claiming no religion has gone from 8.2% in 1990, to 14.2% in 2001, and now 15% in 2008. US population has risen from 207 million to 228 million since the last census was taken, so that small rise actually translates into an additional 4.7 million who say "none." From a regional standpoint, Northern New England has now taken over from the Pacific Northwest as the least religious section of the country, with Vermont, at 34 percent "Nones," leading all other states by a full 9 points.
Catholics remain the largest religious group nationwide, with 57 million people saying they belong to the Church. Catholicism has gained 11 million followers since 1990, but its share of the population fell by about a percentage point to 25 percent. Catholics make up a third of the adult population in California and Texas, and a fourth of Florida, primarily due to Latino immigrants. Baptists are the second largest Christian denomination.
Other key findings of the study include:
The percentage of Christians in America, which declined in the 1990s from 86.2 percent to 76.7 percent, has now edged down to 76 percent. Ninety percent of the decline comes from the non-Catholic segment of the Christian population, largely from the mainline denominations, including Methodists, Lutherans, Presbyterians, Episcopalians/Anglicans, and the United Church of Christ. These groups, whose proportion of the American population shrank from 18.7 percent in 1990 to 17.2 percent in 2001, all experienced sharp numerical declines this decade and now constitute just 12.9 percent.
Most of the growth in the Christian population occurred among those who would identify only as "Christian," "Evangelical/Born Again," or "non-denominational Christian." The last of these, associated with the growth of megachurches, has increased from less than 200,000 in 1990 to 2.5 million in 2001 to over 8 million today. These groups grew from 5 percent of the population in 1990 to 8.5 percent in 2001 to 11.8 percent in 2008. Significantly, 38.6 percent of mainline Protestants now also identify themselves as evangelical or born again.
"It looks like the two-party system of American Protestantism--mainline versus evangelical--is collapsing," said Mark Silk, director of the Public Values Program. "A generic form of evangelicalism is emerging as the normative form of non-Catholic Christianity in the United State s."
Other key findings:
• Baptists, who constitute the largest non-Catholic Christian tradition, have increased their numbers by two million since 2001, but continue to decline as a proportion of the population.
• Mormons have increased in numbers enough to hold their own proportionally, at 1.4 percent of the population.
• The Muslim proportion of the population continues to grow, from .3 percent in 1990 to .5 percent in 2001 to .6 percent in 2008.
• The number of adherents of Eastern Religions, which more than doubled in the 1990s, has declined slightly, from just over two million to just under. Asian Americans are substantially more likely to indicate no religious identity than other racial or ethnic groups.
• Those who identify religiously as Jews continue to decline numerically, from 3.1 million in 1990 to 2.8 million in 2001 to 2.7 million in 2008--1.2 percent of the population. Defined to include those who identify as Jews by ethnicity alone, the American Jewish population has remained stable over the past two decades.
• Only 1.6 percent of Americans call themselves atheist or agnostic. But based on stated beliefs, 12 percent are atheist (no God) or agnostic (unsure), while 12 percent more are deistic (believe in a higher power but not a personal God). The number of outright atheists has nearly doubled since 2001, from 900 thousand to 1.6 million. Twenty-seven percent of Americans do not expect a religious funeral at their death.
• Adherents of New Religious movements, including Wiccans and self-described pagans, have grown faster this decade than in the 1990s.
Researchers plan a broader survey on Jews who consider themselves culturally Jewish but aren't religiously observant, as that percentage increases at a rapid rate.
Chart from the Associated Press article here.