What's the longest stretch of time you cannot remember/recall?

Is there any year/s you cannot account for? Other than being an infant up until your memory of things and events started to develope, is there a year or years you don’t recall? For example, I don’t remember the years when I was 9 to 11 years old. I remember being 8, as I recall I was 7 going on 8 when my sister was born, and after that I seem to draw a blank.. Between 8–11 years old I can’t seem to recall any activities or events, and I don’t remember me.

I can understand not remembering short durations of times or events in life, but to not remember years at a stretch; does this seem common or normal? Do you have loooong stretches of time you don’t recall?