That's a lot of members to lose. I hope those are people who haven't lost faith, just moved to a more mainstream church. In Europe the membership has been declining as faith plays a much smaller role in the lives of Europeans. I'd hate to see the US move in that direction.
In the US, Evangelical churches are popping up and their membership growing, while the old "mainline" Protestant churches lose membership.
The new evangelical Churches may not have the grand churches, but they have what counts, people in the pews.