I was going to do some cheesy calculation based on extrapolating out to the entire world from the data in that report but I've found something more interesting. The US Census Bureau publishes that the world has an estimated population of 6,779,885,336 at the time I looked. They have a note to say that they don't actually know the population down to the last person but it is still a little silly to publish it like that. Each time you refresh, the number slowly increments.