Numbers for Fantasy Worlds
From the introduction:
Fantasy worlds come in many varieties, from the "hard core" medieval-simulation school to the more fanciful realms of high fantasy, with alabaster castles and jeweled gardens in the place of the more traditional muddy squalor. Despite their differences, these share a vital common element: ordinary people. Most realms of fantasy, no matter how baroque or magical, can not get by without a supply of ordinary farmers, merchants, quarreling princes and palace guards. Clustered into villages and crowding the cities, they provide the human backdrop for adventure.