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

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

Similarly, the latest Gallup survey finds a decline in belief in God. When asked specifically if they believe in God, 81 percent of Americans said “yes,” the lowest percentage in the history of the survey.

According to the GSS data, most of those who have left behind certainty in God’s existence haven’t moved to certainty in the opposite direction. Since 1993, the percentage of those who say they don’t believe in God has only risen from 3 percent to 7 percent. Agnosticism, not knowing if there’s a God and believing there’s no way to find out, is up from 4 percent to 7 percent. The percentage of those who say they believe in some higher power has increased from 8 percent to 14 percent. And the percentage who believe in God sometimes has ticked up from 3 percent to 6 percent.

Groups least likely to know God exists

Sure, belief in God has particularly fallen among young adults. In 1993, 63 percent of 18- to 34-year-olds knew God existed with no doubts. Today, just 36 percent 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 percent. 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 percent.

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

Among marital status, there is a growing gap between never-married adults and everyone else. Most other groups—married, divorced and widowed—show a declining trend in confident belief in God. For those who have never married, however, the drop has been precipitous—from 57 percent in 1993 to 34 percent today.

Politically speaking, a God gap has emerged that didn’t exist 20 years ago. In 1993, Republicans (67 percent) and Democrats (66 percent) were just as likely to express confidence in God’s existence. Independents weren’t far behind at 61 percent. Now, while 67 percent of Republicans still say they know God exists and have no doubts, belief among Independents has dropped 14 points to 47 percent and Democrats have fallen 26 points to 40 percent.

Among ethnic groups, confidence in God’s existence has remained fairly steady among Black Americans. In 1993, 79 percent knew God existed without any doubts, while 73 percent say so today. Among non-Black minorities, the percentage who confidently say God exists dropped from 60 percent to 52 percent. For white American adults, however, those who express certainty in God’s existence fell from 63 percent to 46 percent.

While women are still more likely than men to say they know God exists without any doubts, the gender gap is narrowing. In 1993, 72 percent of women had confidence in God’s existence and 56 percent of men said the same. Now, 55 percent of women and 44 percent of men have the same levels of certainty—a 17-point drop among women and a 12-point decline for men.