(ANALYSIS) I’ve got a lot of data visualizations in the post today, and I don’t want to make it overly long. So, let me just get right to the graph that started me down this rabbit hole.

It’s from the General Social Survey, and I am just looking at respondents who are between the ages of 18 and 35.

For very keen observers of this newsletter, you will notice that this graph has appeared once before in a post titled, “Four of the Most Dramatic Shifts in American Religion Over the Last 50 Years.”

Well, it’s updated now with data from the last couple of waves from the GSS.

The highlighted period is one that I wanted to focus all my attention on — it spans from 1991 to 1998. In my estimation, this is the most consequential period of American religious history in the past five decades.

For the 20 years prior, the share of young Americans who were Christians was about 85%, while the nonreligious portion never moved above 10%. But in the little seven-year window of time, everything changed for young adults.

In 1991, Christians were 87% of the sample. In 1998, it was 73%. The share who were nonreligious went from 8% to 20% during that same time period.

How long did it take for the Christian share to drop another 14 points? It didn’t happen until 2018.

How about the nones jumping up by a dozen points? Again, it was 2018.

But how did this happen? Did evangelicals take a nosedive? Did the Catholic Church hemorrhage a bunch of folks? For some reason, I hadn’t really thought much about investigating that until now. So, let’s get to work.

This is the evangelical share of the 18-35-year-old sample from the General Social Survey.

For the next couple of graphs, I am going to show you the entire time series so that you can get a sense of how the 1991-1998 window fits into the larger picture.

In the early 1970s, about 20% of young adults were evangelical, but that share slowly began to rise over the subsequent decades. By 1990, it was nearly 25% of those 18-35.

What’s interesting is that it appears evangelicals were at their peak in the early 1990s. But they slowly began to fall over the next 10-15 years.

By 2012, they were in the same place they were 40 years earlier. Currently the share of young adults who are evangelical is about 13%. But during that seven-year window of time, we can see that evangelicalism only really dropped by about three points.

That certainly is not enough to explain the first graph.

To read the rest of Ryan Burge’s column, please visit his Substack page.

Ryan Burge is an assistant professor of political science at Eastern Illinois University, a pastor in the American Baptist Church and the co-founder and frequent contributor to Religion in Public, a forum for scholars of religion and politics to make their work accessible to a more general audience. His research focuses on the intersection of religiosity and political behavior, especially in the U.S. Follow him on X at @ryanburge.