Americans who have been paying attention to arguments about religion in recent years know that two statistics have caused the most chatter in the digital public square, as well as coverage in the old-school press.

First, there was the omnipresent statistic from 2016 polls indicating that 81% of white evangelicals backed Donald Trump. Meanwhile, the thrice-married New York billionaire captured 60% of white Catholic votes and -- here's the shocker -- 58% of votes by "Protestant-other" Christians, a niche dominated by America's more progressive mainline churches.

But that wasn't the hottest of the hot statistics, the one that caused a tsunami of debates about the future of American religion. That honor would have to go to the Pew Research Center's reports on the soaring number of people who are "religiously unaffiliated," or "Nones." In 2012, Pew noted that "Nones" had quickly risen to be one-fifth of the U.S. public.

Earlier this year, political scientist Ryan P. Burge of Eastern Illinois University dug into the 2018 General Social Survey, crunched some data and then took to Twitter to note that Americans with ties to no particular religious tradition were now about 23% of the population. That percentage is slightly higher than evangelical Protestantism and almost exactly the same as Roman Catholicism.

"At that point my phone went crazy and I started hearing from everyone" in the mainstream media, said Burge, who is co-founder of the Religion In Public weblog. "All of a sudden it was time to talk about the 'Nones' all over again."

Burge recently started another hot discussion on Twitter with some GSS statistics showing trends among believers -- young and old -- in several crucial flocks. For example, "19.9% of young people are evangelical, compared to 22.9% of those over 65." At the same time, "21% of young people are Catholic. Compared to 24.3% of those 65+."

Those stats show some decline, but not collapse. Then again, Burge noted that, "4.5% of those under 35 are mainline Prot. vs. 20.6% of those 65+."