Are we counting clean misses or just shots on an animal that you ultimately killed?
i say the number of shots taken before punching the tag, miss on a different animal or not.
really it should almost be a shots per tag ratio to capture what i think the ratio should capture in my mind - which is the ability to hunt effectively, efficiently, carefully, slowly, get close, think before your shots etc. i kind of also think of it as the "ethical ratio"