The general population of La Paz is about 250,000 and it’s about the same for San Jose and Cabo combined. However, I’m not sure the percentage of the population who are the expats. Here in La Ventana, where I live, the local Mexican community is about 1,600 and during the high season, we get about 2,500 expats here. There are actually more Canadians and Americans than Mexicans in La Ventana during the high season. In the low season, there’s about a couple hundred expats living here full time.
There is a concentration of expats in La Paz, specifically in El Centenario, which is going north from La Paz as if you would be driving back to Tijuana or San Diego to the border. There are a couple master-planned communities in El Centenario, too.
Compared to La Paz, there are a lot more expats in Cabo, although people who buy in Cabo versus people who buy in La Paz are very different types of people; they are looking for very different lifestyles. People who buy in La Paz are looking for a more low key lifestyle, which is focused a little bit more on outdoor sports. They probably are more interested in learning how to speak Spanish and actually socializing with the Mexican community, whereas as in Cabo, it is more Americanized and people there are more interested in having a wider variety of restaurants and more tourist activities.
(View from a boat of El Centenario, Baja California Sur, Mexico, pictured.)