Good info on the reasoning for not continueing the "first year free" program.
Not to repeat myself, but the important question to answer is "why?" Why did only 15% renew their membership? I think the answer may prove out my earlier point...we have to make membership rewarding to keep members...maybe, just maybe, the new members did not believe the membership was worthwhile.
I personally do feel that being a member has its rewards, but I didn't come by that opinion on my own, it took all the great members I met to open my eyes to all that is available and the community that exists for our mutual benefit.
By the way, by most marketing standards, 15% is not a bad return rate from a "first year free" promotion. It wouldn't take much to get that up to say 25%, which is a very good return rate.