Women are at a much higher risk than men of facing economic uncertainty in retirement and, on average, they'll enter retirement with considerably less savings than men, said the report, "The Female Factor 2008: Why Women are at Greater Financial Risk in Retirement" by the Women's Institute for a Secure Retirement.

"With more years out of the workforce to care for family, combined with lower wages and a greater life expectancy, it's clear that simply being a woman in our society may jeopardize your financial security," study author Cindy Hounsell, president of Women's Institute for a Secure Retirement, said in a statement.

Older women living alone -- whether widowed, divorced or never married -- face much higher rates of poverty than men, the report said. Approximately 20 percent of unmarried elderly women are poor.

The report also said that:

-- More than one in 10 female retirees and one in five single women over age 65 live on less than $10,000 a year.

-- The average Social Security benefit for women is $800 per month, compared to $1,177 for men.