Even among those who do have retirement savings, their nest eggs are small. The agency found the median amount of those savings is about $104,000 for households with members between 55 and 64 years old and $148,000 for households with members 65 to 74 years old. That's equivalent to an inflation-protected annuity of $310 and $649 per month, respectively, according to the GAO.
"I don't care what anyone says. That's not enough income for retirement," said Anthony Webb, senior research economist at the Center for Retirement Research at Boston College, who reviewed the GAO report.
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Social Security remains a fundamental part of most Americans' retirement plans, with benefits providing most of the income for about half of households age 65 and older, according to the GAO.
The agency studied the level of Americans' retirement savings at the request of Sen. Bernie Sanders of Vermont, an independent who is seeking the Democratic nomination in the 2016 presidential election and is also the ranking Democratic member on the Senate's subcommittee on primary health and retirement security.
Estimates about the size and scope of the retirement savings problem vary widely, the GAO found. In addition to examining the Survey of Consumer Finances, it reviewed nine studies conducted between 2006 and 2015 by a variety of organizations, including academics, benefits consultant Aon Hewitt, the Employee Benefit Research Institute (EBRI) and the Investment Company Institute. Based on these reports, it concluded that one-third to two-thirds of workers are at risk of falling short of their retirement savings targets, in part because of the range of assumptions about how much income is required in retirement.
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The research that the GAO examined consistently showed that people aged 55 to 64 are less confident about their retirement and plan to work longer to afford retirement. However, a 2012 study by the EBRI found that about half of retirees said they retired earlier than planned because of health problems, changes at their workplace or having to care for a spouse or another family member. This suggests "that many workers may be overestimating their future retirement income and savings," wrote GAO researchers.
"EBRI's model does show that a significant percentage of households will run short of money in retirement," said Jack VanDerhei, EBRI's research director. "This is because we model all the major risks in retirement."
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Reports like those and the GAO analysis should serve as a wake-up call about the lack of Americans' retirement savings, said Catherine Collinson, president of the Transamerica Center for Retirement Studies.
Transamerica's retirement research, which wasn't included in the GAO's review, doesn't give board projections about America's retirement readiness because retirement is "a very personal question," she said. But Collinson stressed the need for more people to calculate their projected retirement needs and to plan ahead accordingly. "As a society, we cannot do enough to raise awareness about the magnitude of this problem."