It's pretty remarkable how much of the total population to have ever lived is alive today or recently. This is especially true if you consider how many of the past deaths were of young children. Just roughly, assuming half of the preindustrial deaths were of children, leaves about 8/55 billion, or 14.5 percent of adult persons ever living today, or at the time of the figure. That's still small overall but pretty huge for the timeframes involved.<p>I really think people haven't come to terms with how unusual our era is.