Nearly 85% of folks who were raised Catholic were still a member of that faith group when they were interviewed. For Protestants it was even higher – over 90%. Christians just didn’t move around a whole lot back in those days. However, among those who raised without religion, the vast majority picked a faith tradition as they moved into adult-hood. That was the case for 2/3 of those raised nones in the 1970s.
However, those trends lines have not stayed flat over the last five decades. Retention is down for all Christians, but at different rates. For Catholics, it dropped below 80% somewhere in the early 1990s and it fell below 70% in the early 2010s. For Protestants, it’s still fairly high but is clearly down from the 90% reported in the 1970s. Today, about 80% of folks raised Protestant are still Protestant as adults.
The nones are different story entirely, though. It used to be that 2/3 of those raised nones identified with a religion as adults. Now, about 2/3 of those raised with no faith group are still nones into adulthood. In other words, most people raised none are still a none now. .
Evangelicals have very good retention rates, even in the last decade nearly three quarters were still part of the same faith tradition as adults. The overall retention decline for evangelicals is just five percentage points. For mainline it’s much worse. They started right around the same level as evangelicals (76%), but now it’s just 58%. That means that if you found five people who were raised in the mainline, two of them would no longer be mainline today.