I'd estimate 5-6% for me - a few on the PS2 and Gamecube, one PS1 game (Turnabout), one GBA game (Open Season, which I acquired a couple weeks ago for $1.58 at Fred Meyer), and one DS game (Looney Tunes: Duck Amuck, which I bought last week at Target, and coincidentally, is the only DS game I've purchased all year that wasn't used).

Then again, I rarely buy new games and if I do, it's usually something that I'll open and play right away, or it's on sale (Duck Amuck) or clearance (Turnabout and Open Season).