Slightly over half those workers with access to employer-sponsored plans participated in 2001, according to the Congressional Research Service analysis of Census Bureau data. The study looked at 113 million workers ages 25 to 64 who earned money on the job, including full-time, part-time, private, public and self-employed.
"Our savings rates here are a disaster, and the study continues to beat home the crisis in savings overall," said Derrick Max, executive director of the Alliance for Worker Retirement Security, which represents business groups and favors overhauling Social Security to add personal retirement accounts.
Max said the report bolsters support for Social Security private accounts, which President Bush supports but Democrats oppose. Social Security is projected to start paying out more in benefits than it takes in from payroll taxes by 2016 because the large baby boom generation begins retiring. The work force size will be smaller, and demand for benefits will grow.
"The uncertain future of Social Security and the declining prevalence of traditional defined-benefit pensions that provide a guaranteed lifelong annuity have put much of the responsibility for preparing for retirement on the shoulders of the worker," the report said.
The 401(k) accounts were the most popular form of retirement savings, with one in three workers participating, the report said. About 19 percent owned an IRA or a Keogh account for self-employed workers. Almost 42 percent owned one or more retirement accounts.
For the 47.1 million workers with at least one retirement savings plan, the average account balance for a single employee was $45,960. For households, it was $71,040.
Of older workers ages 55 to 64, three out of four lived in households with retirement savings of zero to $56,000.
For older workers with savings, the average single-account balance was $71,910 and the household balance was $107,040.
The report "highlights the lack of retirement security millions of Americans face," said Rep. George Miller of California, ranking Democrat on the House Workforce and Education Committee.
He cited the Treasury Department decision this week to pursue new government regulations that would help companies avoid age-discrimination lawsuits when they convert traditional pension benefits to different arrangements called cash-balance plans.
In such a plan, an employer credits to a worker a percentage of the worker's wages and decides what interest rate it will earn. When a worker leaves the employ of a business, the amounts credited are turned over to the worker.
Unlike 401(k) plans, workers don't own a retirement account nor do they make investment decisions. Unlike a traditional pension plan, the worker isn't guaranteed annual benefits after retiring. Critics say cash-balance plans hurt workers nearing retirement.
President Bush "should read this report before he decides to undercut what little retirement security is left for hardworking Americans," Miller said.
Only about 30 percent of workers participate in traditional pension plans sponsored by employers that provide guaranteed annual benefits for life. Companies are cutting those benefits in favor of 401(k)s and cash balance plans because they are less expensive to administer.