I put myself in the 90-99% category. Not 100% because I often have a pint at the pub at lunch time.
I have been able to track how good my brewing is getting by how much commercial beer I keep around and drink. When I first started brewing, I was drinking plenty of homebrew but generally always had some commercial beer hanging around, and the commercial beer was generally better than my beer.
As my brewing has become better the number of commercial beer purchases has decreased sharply, being restricted to when I'm having non-HB friendly people over or want to get some give-away glass.
Now that I'm kegging and brewing consistently good quality all-grain, the usual situation is that I have plenty of good homebrew on tap and no commercial beer in the fridge at all.
My tastes have also changed, so when I do buy commercial beer its quite different beers to what I was buying when I started out.