The National Bureau of Economic Research stated that the recession began in December 2007 and ended in June 2009.¹ Estimates from the 2009 American Community Survey (ACS) and the 2010 ACS show the continuing effects of the recession, as no state showed an increase in household income while many showed declines.

This report presents data on median household income at the national and state levels based on the 2009 and 2010 ACS.² The ACS provides detailed estimates of demographic, social, economic, and housing characteristics for states, congressional districts, counties, places, and other localities every year. A description of the ACS is provided in the text box “What Is the American Community Survey?”

In the 2010 ACS, information on income was collected between January and December 2010 and people were asked about income for the previous 12 months (the income reference period). This yielded a total income time span covering 23 months (January 2009 to November 2010).³ Therefore, adjacent ACS years have income reference months in common and comparing 2010 economic conditions with those in 2009 will not be precise.⁴

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¹ See <www.nber.org/cycles/sept2010.html> for more information.
² The text of this report discusses data for the United States, including the 50 states and the District of Columbia. Data for the Commonwealth of Puerto Rico, collected with the Puerto Rico Community Survey, are shown in the table, Figure 1, and Figure 2.
³ All income data are inflation adjusted to 2010 dollars. “Real” refers to income after adjusting for inflation.
⁴ For a discussion of this and related issues, see Hogan, Howard, ”Measuring Population Change Using the American Community Survey,” Applied Demography in the 21st Century, Steven H. Murdock and David A. Swanson eds., Springer Netherlands, 2008.