Your target should be to increase your current percentage. I have no idea what an average players percentage is guess it's a matter of opinion, one guy might say 25% and another may say 30%. I think the best way to gauge success is to see if you're improving. Also, ITM itself can be very vague, you have to look at winnings too. Two guys may have same percentages, same tournaments played, and same stakes, but have different earnings. Set goals and keep track of stats i.e. dates, entrants, placings, and earnings.