WASHINGTON – More than 20 million U.S. workers lack health insurance, according to the Center for Economic and Policy Research.

A report from the center indicates that almost 17 percent of workers in 2008 had no health insurance of any form, up from 7 percent without coverage in 1979. The report reviews government data on health insurance coverage from 1979-2008 and focuses exclusively on workers.

"Over 20 million of the 46 million Americans without health insurance are working for a living," said John Schmitt, an economist at the CEPR and co-author of the report.

The biggest reason for the decline in coverage since 1979 has been a fall in employer-provided coverage, the report indicates.

"Coverage rates have fallen sharply over the last three decades," said Schmitt. "If we had maintained the same coverage rate we had in 1979, almost 13 million more workers would have coverage today."

Low-wage workers are the least likely to have health insurance. In 2008, 37 percent of low-wage workers had no health insurance, private or public. About 12 percent of middle-waged workers lacked coverage, also.

Other report findings:

• In 2008, 75 percent of workers had coverage through an employer. Of these, a large majority had coverage through their own employer, and a smaller share had coverage through a family member's employer.
• In 2008, 7 percent of all workers had some form of public health insurance. Medicaid was the most important type of public health insurance for workers, covering almost 4 percent of all workers. Medicare covered a small share of workers (0.4 percent), and other forms of publicly provided health insurance, including military and veterans' healthcare, covered almost 3 percent.
• In 2008, only 5.5 percent of workers had health insurance purchased directly from insurers.
• The 4 percentage-point increase in public coverage rates for low-wage workers between 1979 and 2008 was not enough to make up for a 25 percentage-point decline in private (mostly employer-provided) coverage.