Nearly half of Americans have no money set aside for retirement, according to a new study by the National Institute on Retirement Security.

Forty-five percent, or 40 million working Americans, have no retirement assets, according to The Continuing Retirement Savings Crisis, a study that was the subject of a webinar by NRIS Wednesday. Additionally, the median retirement account balance for all households, including those without retirement accounts, has dipped to $2,500 for working-age American households, down from $3,000 two years ago.

Just as disturbing, according to NIRS, is that for households headed by someone 55 to 64 years of age, the median retirement account balance is $14,500. Also, 62 percent of those households have retirement savings of less than one year's annual income, which is far below what Americans need to be self-sufficient in retirement.

The report by NIRS, a nonprofit organization that studies retirement issues in Washington, D.C., is based on an analysis of the Survey of Consumer Finances from the U.S. Federal Reserve System. The study reinforces an NIRS public opinion poll released earlier this month that found that 86 percent of Americans believe the nation is facing a retirement crisis and 75 percent are concerned about their ability to achieve a secure retirement.

"It's no wonder Americans believe the nation faces a retirement crisis [because] the evidence is irrefutable that the hope of retirement is out of reach for millions of middle-class Americans," says Diane Oakley, NIRS executive director. "Our research finds that the typical near-retirement working household has about $14,500 in retirement savings. This amount won't even replace one year's salary for millions of older Americans. Unfortunately, they just don't have time to catch up on their savings shortfall."

"Two problems are at the heart of the issue: lack of access to retirement plans, particularly among low-income workers and families, and low levels of retirement savings," she said. "These twin challenges amount to a severe retirement crisis that, if left unaddressed, will result in grave consequences for the U.S. economy and families."

NIRS advocates using public policy to assist Americans in retirement. "Social Security, the primary edifice of retirement income security, could be strengthened to stabilize retirement financing and enhance benefits for vulnerable populations. Access to workplace retirement plans could be expanded by making it easier for private employers to sponsor defined benefit pensions. Finally, expanding the Saver's Credit and making it refundable could help boost the retirement savings for lower-income families," NIRS says.