See my post 9.
And, it seems, little room for growth—according to this article, only about 20% of all South Koreans view protestants positively, which means that outside of those who are actually members, they are not a beacon shining out in a positive way—with only about 1 in 12 non-Christians viewing them positively. http://www.koreabang.com/2014/stories/poll-finds-only-20-of-koreans-trust-protestant-church.html