Income level (on the horizontal axis) with the proportion of people in that income bracket who are in finance, real estate or closely related to either (e.g. mortgage broker, lawyer working primarily for financial clients) on the vertical axis. I would guess it shoots up to close to 100% for very high income levels.
To put this another way: I would guess that when you see someone driving a really expensive car, most of the time they will be people who benefitted from the upside of the bubble. And are now leaving you (and your kids) to deal with the downside.
Too pessimistic? Maybe, but I'd love to see the data.