Almost one in five elderly American households outspent their income by more than 50% in 2009 and some (14.3%) outspent their income by more than 175%, according to a new report from the Employee Benefit Research Institute.

The most vulnerable groups were singles, households with no pensions, African-Americans and Hispanics.

“Those with an income shortfall are far more likely to be low-income, low-asset households, and they spend down their liquid assets at a far faster rate than households that do not have an income shortfall,” Sudipto Banerjee, EBRI research associate and author of the report, said in a statement.

The report showed that social security remains the primary source of income for all adults over the age of 65. In 2009, households ages 65 – 74 and households with members over 85 received 54% and 66% of their total household incomes, respectively, from social security.

According to the report, elderly Americans rely more on social security as they age. For households that had members ages 65 – 69 in 2001, the share of household income derived from social security rose from 47% in 2001 to almost 60% in 2009.