82.75 per year, that being 331 over 4 years. Sheesh. I have noticed it getting a little (heh) out of hand; consequently I only bought 3 things (Serious Sam 3 DLC, Serious Sam: Second, and System Shock 2) this latest sale (and the past few similarily).
I only play games I'm really in the mood for these days, so I suspect I'll never play a large portion of what I've bought. Playing FF9 right now :)
This is a really good read for anyone with a chronic buying problem and/or backlog syndrome: