The Southern Baptist have always prided themselves on their continued growth as a denomination. I suspect that pride will continue as an historical accomplishment but it is no longer true. Here’s 2 graphs:
Tim Keller had the following to say about the growth of evangelical Christianity in a November 2007 post on Missional Chuch Network:
“Isn’t evangelical Christianity growing-at least in North America? Look at all the megachurches spouting up! But we must remember that the new situation Lloyd-Jones was describing has spread in stages. It was in Europe before North America. It was in cities before it was in the rest of the society. In the United States it has strengthened in the Northeast and the West Coast first. In many places, especially in the South and Midwest, there is still a residue of more conservative society where people maintain traditional values.
“Many of these people are therefore still reachable with the fairly superficial, older evangelism programs of the past. And if we are honest, we should admit that many churches are growing large without any evangelism at all. If a church can present unusually good preaching and family ministries and programming, it can easily attract the remaining traditional people and siphon off Christians from all the other churches in a thirty-mile radius. This is easier now than ever because people are very mobile, less tied into their local communities, and less loyal to institutions that don’t meet their immediate needs. But despite the growth of megachurches through these dynamics, there is no evidence that the number of churchgoers in the United States is significantly increasing.”