In a new book, "God Is Alive and Well: The Future of Religion in America," Gallup describes the results of 320,000 interviews conducted from Jan. 2 to Nov. 30. Forty percent of those interviewed say they attend church at least once a week while 69 percent say they are religious.
The poll found that women across race and age groups are more religious than men, blacks are the most religious racial minority and Mormons the most observant of any religious group, while Jews are the least observant. Religious belief is highest in the south and lowest in the northeast (Vermont, Maine and New Hampshire) and northwest (Oregon, Washington and Alaska).
While people with low incomes tend to be more religious, upper-income residents are more likely to be regular churchgoers. Whites who identify themselves as religious are more likely to be Republican while blacks are likely to be religious and are more like to be Democrats.
Slightly more than half of U.S. residents identify as Protestants, 23 percent as Catholics and 18 percent say they have no formal religious identity. Only small percentages describe themselves as non-Christian, including Jews, Muslims and Buddhists.
The percentage of those not identifying with a specific religious group has increased along with the number of community churches and other churches with loose or no ties to traditional denominations.
The findings are based on Gallup's Daily Tracking poll. The margin of error is 1 percentage point.