THE NUMBER OF HOUSEHOLDS spending more than half of their incomes on housing jumped to 17.9 million in 2007, a 30 percent hike from 2001, according to the new State of the Nation's Housing report from Harvard University's Joint Center for Housing Studies.

Nearly 51 percent of low-income renters and 43 percent of low-income owners paid more than half of their incomes for housing.

High housing outlays leave little money in the budget. Low-income families had about $485 per month for everything else. Households in the bottom expenditure quartile devoting more than half their spending to housing on average spent $123 less each month on food, $86 less on health care, and $20 less on clothing than households paying less than 30 percent for housing.