My maternal grandfather died of a stroke when I was about 12 years old; my paternal grandfather died of cancer when I was 19. Those are the only people I knew personally who have died, and I think those numbers (and causes of death) are fairly typical for young people. I've seen lots more dead people, as a nursing student, including some who died of accidental/preventable causes, but I don't count that as evidence I can generalize from–it's a massively biased sample.