purrpurr - When I was coming along in the mid-eighties It was put to me this way:
1. World pop in 1987 could fit shoulder to shoulder on the Isle of Wight. It was just over 5 billion at the time.
2. The amount of people who'd ever lived & died up to 1987 could fit shoulder to shoulder on Madagascar. The
total - 108 billion ( 2 separate sources).
I've never given it any thought till your post.