Where's All the Expats?

When we first moved to Beijing, we were amazed out how few expats we'd see while walking around the neighborhood. Since we live in the Chaoyang Park area, we basically live in expat central but, strangely, no expats. Where are they?
In the intervening months, I've come to realize a few things. First of all, since we first showed up around the end of the summer, none of the expats were walking the streets. It's hot enough (and the taxis are cheap enough) that any self-respecting expat will not bother being outside. Air conditioning all the way.
The other reason is that there just aren't that many expats around. Beijing has about 50,000 expats total (out of a population of 15+ million). It seems like that would be enough to see them out on the streets until I discovered that 40,000 of them are east-asian expats (mostly from Korea and then Japan). That leaves only 10,000 western/south-asian expats remaining. That's apparently not enough people to notice in any large groups in the city. Of course, visit any pricy bar or upscale restaurant and you'll find all the expats you need to find.
On a similar note, I was recently talking to some Brazilians and they made a comment on how multi-cultural Beijing was and how many foreigners there were in Beijing. I asked them what the hell they were talking about. I mean, as far as I'm concerned, there's almost no foreigners in Beijing (50,000 out of 15,000,000+). I never see them out and about. They looked at me and then just started laughing. Their comment? (paraphrased):
"You Americans are so silly. You think all cities in the world should have as many foreigners as your cities. Compared to the rest of the world, Beijing has tons of foreigners." I was appropriately chastised. Funny that an expectation of a truly multi-cultural society would brand me as small-minded. Strange world.