As a world designer, I have never been very happy with the way that NPCs were handled as D&D developed, and that has run through into Pathfinder, and there have been too many hangovers from earlier editions, that don't quite work anymore. Instead, I use an overall of demographic of (roughly) 60% commoners, 30% other NPC classes and about 5-10% PC classes when I am world building. However, the proportions vary according to the area.

Most NPCs are Level 1, Level 2 characters are supervisors while established NPCs, with good training in a 'proper' career, are generally level 3. Soldiers, Town Guards, Clergy, Managers and Leaders all fall into this category. Higher level NPCs probably need to be a recurring character with both a name and a character sheet.

These pages describe the way I use NPC Classes.

Commoners - Never quite fitted in. They are just good enough that they almost make Experts redundant on a day-to-day basis. So a slight rework, but without too many changes.

Adepts - I have never liked the way that Adepts are written, they really don't model any spell casting class well. While I do use the standard cleric occasionally, I have a set of Adept Archetypes that model the casting classes much more effectively.

Warriors - The Warrior is a simplified fighter-type that serves well for the bulk of the army and town guard, that can be developed into specialists, with standard builds, at higher levels. They will never compete with PC classes, but they provide a decent team for a PC to lead.

Experts

Aristocrats - The basic Aristocrat is quite nice, but it assumes that all aristocrats rule by the strength of their arm. I have a couple of other ideas.