While the article is 8 years old, everything I have read lately indicates that this is still true.
On another thread, OP was relaying that both Protestantism and Calvinism (worldwide, I believe) were growing at a decent clip.
Only thing I've read recently regarding the growth of Evangelical Churches, is that Roman Catholicism appears to be losing ground to them in Latin America.
The explanation offered for this goes something like 'we've got Larry Kudow, Laura Ingraham, Scott Hahn and Karl Keating, while you have, ahem, AlbionGirl. In the parlance of a country song, 'we got the gold mine, you got the shaft', so, sorry for that my friend.
The thing that strikes this corn-fed, country girl the most is that Protestant converts to Catholicism were able to convert in large measure because they were given the freedom to explore. That freedom, that blessed Protestant ethic, speaks for itself, and is of inestimable import and value.
Another thing that strikes me, is the difference between the Protestant, that is the OPC, and Catholic make-up as it concerns whose running things at the local level.
The RCC (at least in my experience) is being run at the local level mainly by females. The men seem definitely AWOL, and I think that's a huge problem. To sort of paraphrase Tip O'Neill: all religion is local.
The OPC on the other hand, seems to have been able to retain a very strong commitment on the part of the men in their midst, who seem to take Church discipline quite seriously. It seems a very well-run and transparent organization.