Gallup reports that the number of people who think so is at an all time high:

Seven in 10 Americans say religion is losing its influence on American life -- one of the highest such responses in Gallup's 53-year history of asking this question, and significantly higher than in the first half of the past decade.

Americans' views of the influence of religion in the U.S. have fluctuated substantially in the years since 1957, when Gallup first asked this question. At that point, perhaps reflecting the general focus on family values that characterized the Eisenhower era, 69% of Americans said religion was increasing its influence, the most in Gallup's history.

Views of the influence of religion shifted dramatically in the mid-1960s. By 1970, in the midst of the protests over the Vietnam War and general social upheaval, a record 75% of Americans said religion was losing influence in American society. These views moderated in the years thereafter. At several points during the Reagan administration, a plurality of Americans returned to the view that religion was increasing its influence. By the early 1990s, Americans became more convinced again that religion was losing its influence. These views persisted until a sharp reversal after the Sept. 11, 2001, terrorist attacks, when a number of social and political indicators, including presidential and congressional approval and overall satisfaction with the way things were going, showed substantial increases.

Views that religion was increasing in influence began to fade in the second half of the last decade. The 7 in 10 Americans who now say religion is losing its influence is tied with 2009 for the most who have held such a view since 1970.

Not exactly sure what this means. It may be related tangentially to Christian bashing in the media and elsewhere but there was just as much of that in the 1980's when people thought religious influence was on the rise.

One other note from the survey; American's feelings about the impact of religion on them personally has remained steady through the years. That reflects individual family values where children generally see religion as important as their parents.