How many troops are in a cohort?

I understand that it is different for each different troop type.

So, for Mages, how many mages form 1 cohort?
And dragoons, and volunteers, and pikemen.... Archers, and crossbow men..

I have been trying to find this information, but have not been able. Any help would be appreciated.

http://terrabellica.com/~book/1004
Each unit has a description. Also this info is available at the question mark in-game, when you click the troops as a resource.

Ah, great!!! Thanks.