You're browsing the GameFAQs Message Boards as a guest. Sign Up for free (or Log In if you already have an account) to be able to post messages, change how messages are displayed, and view media in posts.
Heres the map of the locations: http://www.primagames.com/games/sleeping-dogs/primaguides/319/gameplay/14231
It's not very well detailed at all, but all the other map locations list only 14 spots where this lists 16 spots. I can verify there are 16, i've bought all of the house upgrades from all 16 locations, it just takes a little bit of wandering in the area where the number is to find a random person with a speech bubble next to their head. Just thought I should post this.