"$33,000 per capita should do the trick quite nicely and still leave a wealthy class"

Bobert: If every person had a $33,000 income, there would be no wealthy class unless you consider $33K wealthy.

I looked for a source that you could trust for the per capita income and at Mother Jones it said $37,610 for the US.

http://www.motherjones.com/news/featurex/2005/01/barrel.html