Three in 10 people in the United States attend religious services on a regular basis, representing a decline compared to the past couple of decades, according to a report by Gallup.

Gallup reported that 21% of Americans said they attend religious services on a weekly basis, while 9% said they attend religious services nearly every week.

By contrast, 11% of respondents reported attending about once a month, 25% reported attending “seldom,” while 31% said they “never” go to religious services.

This represents a decline from one decade ago, when Gallup found that 38% of Americans attended weekly or almost weekly, and from two decades ago, when 42% of Americans reported attending weekly or almost weekly.

Gallup found that Mormons were the most likely to report going to their services regularly, Protestants were the next highest followed by Muslims, and then Catholics.

The report also found that Catholics experienced the sharpest drop in attendance compared to two decades ago, going from 45% regular attendance in 2000-2003 to 33% over the past three years

As for people groups, the largest declines in attendance were seen among adults younger than 50.