I think it depends on the individual. I get gobsmacked at peoples limited memory of history. I find its like 5 but if you one standard deviation over its like 10 and then like 5% its 20 and some small number is likely 40 and then not sure how its like for those folks that seem to be able to remember every detail of their lives. Granted even then its like a feel for who you were and memories of how you handled things or did for particular things you can bring up. Then you have to add in though all that evidence that every time we remember something we have a chance of changing it.