If you hover over the accept rate display, it will tell you how the accept rate was calculated. (It's a fairly complicated thing, with lots of stipulations for eligibility and exceptions.) For yours, I see:
Looking at your profile, I see that the eligible one for which you haven't accepted an answer is this one. It's eligible because it has received at least one answer.
And I'm not very good at math, but my calculator assures me that this works out to be correct:
(32 / 33) * 100 = 96.97 ≈ 97
The two questions with 0 answers (this one, and this one) are not being included because it is impossible to accept an answer when one has not been provided. The fact that one of them has an answer that has since been deleted is irrelevant.
All of that said, seriously? Your accept rate is 97%. You have absolutely no reason to worry about your accept rate. As long as it's over 50%, I promise that you're doing just fine. Most importantly, do not feel forced into accepting an answer just to get your accept rate up. You should only accept an answer when it has actually been helpful to you in solving your problem. If not, leave the question open and let someone else come by and answer it more satisfactorily. There's absolutely nothing wrong with that; in fact, it's completely by design.