Originally Posted by
Tarthalion
It's a fictional world, so obviously it can have any population that the author wants, but the pre-industrial population of our world peaked at about half a billion, so my head canon has the population of all thinking peoples in the OOTS world at or below that level. So it requires that they all believe in Loki and believe he's incapable of telling the truth.
So, I'm going to say it's hyperbole from Loki - just because he can tell the truth to Thor doesn't mean he does, so there's no need to take his believer estimates as even remotely accurate.