While U.S. currency says “In God We Trust,” only half of U.S. adults have certainty about God’s existence.

When asked about their confidence in God’s existence, 50% say they know God exists and have no doubts, according to the latest General Social Survey (GSS). In 1993, 65% of Americans said they were certain God existed, and the percentage has been sliding down ever since.

Belief in God has particularly fallen among young adults. In 1993, 63% of 18- to 34-year-olds knew God existed with no doubts. Today, just 36% have the same confidence. Other age demographics have fallen, but not to the same extent. Belief in the divine among 35- to 49-year-olds is down to 49%. While the percentage of those 50 and older who have complete confidence in God’s existence remains higher than other age groups, it has dropped to 58%.

Belief in God among upper-class Americans has actually increased over the past two decades, from 49% to 53%. But it has declined in every other class designation. Middle-class belief is down from 62% in 1993 to 44%. Working-class belief has declined from 67% to 54%. And lower class belief has dropped from 75% to 57%.