"What is the average yearly household income in the US for 2008?"

However, that last year tracked, 2006, ...

"

In 2006, the median annual household income was $48,201.00 according to the US Census Bureau.^[3] The median income per household member (including all working and nonworking members above the age of 14) was $26,036 in 2006.^[4] In 2005, there were approximately 113,146,000 households in the United States. 19.01% of all households had annual incomes exceeding $100,000,^[5] 12.7% fell below the federal poverty threshold^[6] and the bottom 20% earned less than $20,032.^[7] The aggregate income distribution is highly concentrated towards the top, with the top 6.37% earning roughly one third of all income, and those with upper-middle incomes control a large, though declining, share of the total earned income.^[8][2] Income inequality in the United States, which had decreased slowly after World War II until 1970, began to increase slowly in the 1970s, and has since increased more quickly.^[9] Households in the top quintile, 77% of which had two income earners, had incomes exceeding $40,705. Households in the mid quintile, with a mean of one income earner per household had incomes between $22,000 and $57,657.^[10]

The 2006 economic survey also found that households in the top two income quintiles, those with an annual household income exceeding $60,000, had a median of two income earners while those in the lower quintiles (2nd and middle quintile) had median of only one income earner per household. Due to high unemployment among those in the lowest quintile the median number of income earners for this particular group was zero.^[5] Overall, the United States followed the trend of other developed nations with a relatively large population of relatively affluent households outnumbering the poor. Among those in between the extremes of the income strata are a large number of households with moderately high middle class incomes^[8] and an even larger number of households with moderately low incomes.^[5] While the median household income has increased 30% since 1990, it has increased only slightly when considering inflation. In 1990, the median household income was $30,056 or $44,603 in 2003 dollars. While personal income has remained relatively stagnant over the past few decades, household income has risen due to the rising percentage of households with two or more income earners. Between 1999 and 2004 household income stagnated showing a slight increase since 2004.^[11][12]

go to the link below - lots of cool graphs and cites to reference sites, such as the census bureau.

http://www.census.gov/hhes/www/income/income.html

http://quickfacts.census.gov/qfd/states/00000.html