It depends on genetic and a lot of other things, you maybe never get that number or you may get even more then that, we can’t possible know that.
So I’d say stay consistent and wait it out. It’s boring I know, but it’s worth it, I mean why are you PE-ing? If this is your goal then keep working on yourself, be consistent and be patient brother.
Rome wasn’t built in a day and I understand you’re doing this for 3 years but some people need 5 years, someone needs more then that and someone needs only 2 years we’re all different so you need to accept yourself and your genetics ASAP. Do what you can and the only thing you can control about your results is consistency & patients it’s that simple. Last few words, don’t have any expectations, don’t tell yourself you’re going to gain 2 inches of length or what not but tell yourself “I’m doing PE, I’m serious about it, I’m consistent, I’m smart about it, I’m always warming up and cooling off, I’m PATIENT, and most of all I will succeed”, doesn’t matter how much, it matters that you SUCCEED, that is the goal, success. Best of luck king, don’t give up I believe that you can do this. Stay hard.