انظر http://www.census.gov/compendia/statab/2011/tables/11s0690.pdf؛ وhttp://www.census.gov/compendia/statab/cats/income_expenditures_ poverty_wealth.html.
http://www.census.gov/compendia/statab/ 2011/tables/11s0690.pdf；http://www .census.gov/compendia/statab/cats/income_ expenditures_poverty_wealth.html。