Lore-wise, what's the most/least common Job? (job spoilers)
From most common to least common I'd say:
Dragoon: Everywhere in Ishgard
Ninja: Everywhere in Doma, now quite a few in Limsa Lominsa
Paladin: Sultansworn and some "free-paladins" roaming about
Bard: Moogles are the keeper of the Bard arts and bestow the soul gems and AFs to those whom they consider worthy.
Warrior: Curios Gorge and his brother are the only WARs in Limsa. While the rest are in their village, but the art is slowly dying per generation. Possible some are also wandering as mercenaries
Monks: Most were slaughtered in Ala Mhigo, the rest are in hiding
Black Mage: I can recall 2, but one sacrificed himself. Not sure if the 3 beastmen learned black magic though. Probably the are some black mages in secret
White Mage: Only a select few Padjals can be a WHM. Most speculate that only 3 (the senna siblings) WHM are in existence
Summoner: There was one other SMN. Otherwise those who expose themselves with a primal's aether can theoretically become summoners
Scholar: Need to find a SCH soul gem to get a fairy. Unless you catch one in the wild.
Dark Knight:???
Astologian: Certainly alot more common than WHM or SCH
Machinist: Well, they do have a guild in Ishgard, so I'd imagine is there's alot more machinists than most jobs