I have 7 months worth of images to go through, but thinking about the previous 6 months... I printed 180 out of about 7,000 frames. So that's about 2.5% - which is actually much higher than I thought. Granted, all of these were printed at 4x6 just to give me the ability to let computer-challenged friends & family see them. My standards were lower since that was my first 6 months in photography, but I've also gotten much better since then. In the last 6 months I probably have another 300 that I'd print at 4x6 just to have hard copies.
Now if I consider the "real keepers" that really deserve to get printed then I probably have about 30 or 40 shots that are worthy of 8x10s and frames, and that's out of my "lifetime" of 14,000 images snapped. That's about 0.2%. Out of those, perhaps 8 or 10 are worthy of 16x20 and frames.