How many human beings are/were there?
I'm spinning a story where a guy is chosen to represent the whole of humanity. In this story the minds of people who die are preserved in a cool sword that chooses to communicate with a single person every millennium or so. This enables the guy to glean info from any person that lives or has ever lived.
At some point in the story the guy complains that "I'm in charge of the survival of X billion people." I'd like to have some valid number there.
In short: How many human beings are there? That's an easy one (got some articles in Google), but on top of that, how many humans have died in the history of humanity?
I'd love to have an estimate in the millions, but would be grateful for a billions' estimate.