[fjtorres]

Indy bookstores probably grew a bit--their numbers are increasing--if only because of the B&N closures (the traffic that can't support one B&N can usually support two or three well located indies) and the reduction of shelf space at surviving B&N stores, as well as Wal-Mart and the like. Wouldn't expect the market share growth to be more than a fraction of one percent because, overall, pbook sales volume declined in 2013.
For the most part, people shopping at indies now are those that aren't price sensitive enough to go online and/or who don't have a chain bookstore nearby. With all other B&M pbook shelf space declining, their is a bit of opportunity for well-run indies.

What I can only guess at is the size of the continued decline of the book clubs.
I stopped buying book club editions during the price-fix conspiracy and sometime in 2012-13 they stopped emailing me. Over that time there has been virtually no news about them. The last I heard was they were thinking about getting into ebooks, which they obviously haven't done. Since the time to do something has passed, I don't hold out much hope for them. I have fond memories of the SFBC of decades past. The more recent operation, alas, not so much.
Given that the big ebook adoption spike was 2010-11, we shouldn't be seeing big shifts until the next spike, just gradual erosion of consumer pbook sales.