[umbros]

Number of appearances:

Barbarian 1
Bard 0
Cleric 0
Druid 1
Holy Warrior 0
Knight 1
Martial Artist
Scout 2
Swashbuckler 0
Thief 0
Wizard 3

So ranked thus:

1. Wizard
2. Scout
3. Barbarian, Druid, and Knight.
4. Bard, Cleric, Holy Warrior, Swashbuckler and Thief.