This rapid shift in American religion was driven primarily by evangelicals becoming more prominent in American culture. The rise of televangelists like Jerry Falwell and Pat Robertson coincided with the Religious Right beginning to assert itself in electoral politics. Because the nones were relatively small at this point, there’s ample reason to believe that significant numbers of mainline Protestants became evangelicals through the 1980s.
By the late 1980s, evangelicals had become 25–27 percent of the population, and the mainline population was stuck around 20 percent. In 1993, evangelicals hit their peak in the data at just under 30 percent and have since gone into a slow and steady decline over time.
Between 2000 and 2018, the decline among evangelicals has been relatively modest—just about two percentage points. The mainline also declined three times as fast during this same time period, dropping from 16 percent in 2000 to just over 10 percent in 2018.
When you look at where both traditions started in 1972, evangelicals are slightly up, while the mainline is significantly smaller.
New @CTmagazine from me.
For every 3 mainliners who become evangelicals, there are 2 evangelicals who became mainline.
Evangelicals have relied on that to buoy their numbers for decades. But, as the mainline declines, that won't work going forward. https://t.co/eaBuI8dBuu
— Ryan Burge 📊 (@ryanburge) July 13, 2021