While middle class is a fluid term, common definitions include
- the amount of your family's yearly income,
- acheiving a college degree,
- having a professional occupation, or
- the amount of your family's savings.[1, 2]
I managed to find answers to the first two, and for one, middle class are NOT the majority, and the other the poor constitute a large minority.
- In 2003, 12.5% of the US population lived in poverty, defined as less than "$18,810 for a family of four; $14,680 for a family of three; $12,015 for a family of two; and $9,393 for an individual." This info was difficult to find, as lots of census reports abound, but they go by percentiles rather than histograms, which would be easier to understand.
- In 2004, around 33% of the US population over age 18 had any college degree, or around 25% if you only count bachelor's degrees and higher.
I'm still working on #'s 3 and 4. If you know a reference, comment!