Those numbers are subject to modification. Greyhawk would definitely qualify as “an active adventuring area” and the 1 in 200 would be more appropriate.
Doubling Red Baron’s numbers, it seems about right to me, as a percentage of the normal human population. Plus you can add any number of mercenaries to the total based on p. 18 of WoG '83. Plus you can add 10,600 demi-humans and 10,600 humanoids.