First question is very tricky to put a number to. There are so many variables such as weather, currency, experience, nerves, training etc. etc. that would make any "average" figure questionable.
Second question - almost definitely a "no". I don't think there is a pilot on this forum who would say that they have always made the right call at the right time, however that's part of the constant learning curve that is flying aeroplanes.
Again the decision to "go around" can sometimes be very clear; for example traffic entering the active while you're approaching, or it can be very subjective; the student pilot not feeling comfortably configured for the landing for example. IMO "Getting it right" in this context means taking the safest possible action at any given time, and if that means I need to go around 10 times before I feel comfortable to land safely, then I did "get it right".