The 77 percent who said religion's influence was lessening and the 20 percent who said it was on the rise represent Americans' most negative evaluations of the effects of religion since 1970, Gallup said.
Americans were more likely to say religion's weight was increasing instead of decreasing when the question was first posed in 1957, in 1962, and several times in the 1980s during the Ronald Reagan's presidency; and after the Sept. 11, 2011, terrorist attacks in late 2001 and early 2002, as well as in 2005.
Results indicate 75 percent of Americans asked said it would be positive for society if more Americans were religious, the Princeton, N.J., polling agency said.
In general, Gallup said, highly religious Americans were neither more nor less likely to say religion is losing its influence than those who aren't religious.
The pollster said it found a modest relationship between Americans' ideology, as well as partisanship, and their views of the influence of religion. Liberals and Democrats were more likely than conservatives and Republicans to say religion's influence is increasing in American society.
Results are based on nationwide telephone interviews with 1,535 adults conducted May 2-7. The margin of error is 3 percentage points.