I couldn't find the data on the The National Council of Churches, but do they only report "member" churches? I did notice they have the PCUSA the Reformed Church in America, and the United Church of Christ. All of these, by virtue of their membership, are highly suspect for having liberal theology, or more accurately, humanism. Just look at the issues on the left side of the home page!
I know that the PCUSA is going down the tubes, and has been for years, again, I think it is the liberalism. Just do a search on FR for Presbyterian and you will see several discussions on that very topic.
Is that because of theological perspective?
If you are referring to Calvinism, please allow me to gently set the record straight. We are often accused of not practicing evangelism. We take the Great Commission very seriously. Yes, we think that all events are predestined, but as far as the elect goes, we don't know who they are!
It is out job as believers to spread the Word to all, so those who are meant to come to Christ hear the word through us. To us evangelism is actually very low stress, because the Holy Spirit does all the work, we just have to talk. I don't have to beat myself up if I don't "win" a soul. I've had people who I thought I've done a terrible job with, come to Christ. I've jokingly said that a room of circus chimps would have been just as effective, because the Holy Spirit was working on them. Conversely, I've done what I though was a great job, and not brought some to Christ, but if they watched the resurrection themselves, they would still not believe.
Those that are declining, most were moderate or liberal churches. And the more liberal the denomination, the more they were losing.
Most profound thing I've read on FR today.<><