What kind of city? For a fantasy city, the population breaks down into:

Drunk barroom brawlers 15%
Barkeeps 1%
Barmaids 2%
Beggars 12%
Town Guards 4%
Mysterious Strangers 2%
Harlots 10%
Shopkeepers 3%
Craftsmen 2%
Wizards, Kings, and Misc. 1%
Thieves 48%