How Many High-IQ Wizards?

[David L Pulver]

In Cidri in large cities (such as Dran) I am wondering how many powerful wizards should exist! Specifically, in a city of 15,000 people, such as Dran, the largest on a map the size of Southern Elyntia...

Outside of player character adventurer parties...

... How IQ 15-16 wizards (capable of using potent spells like Create Gate, Long Distance Telepathy and Teleport) are reasonable?

... How many IQ 17-18 wizards (capable of potent spells like Summon Demon, Lesser Magic Item creation) are reasonable?

... How many IQ 19-20 wizards (capable of spells such as Revival, Greater Magic Item Creation or Zombie) are reasonable?

... What do you think the wizard to non-wizard population ratio is?

I'm working on some TFT material for publication, and am curious what people think best fits their conception of the settled areas of Cidri.