Defined contribution retirement plans play a major role in Americans' retirement readiness, according to a report by the American Council of Life Insurers, American Benefits Council and Investment Company Institute.

 DC plans, like 401(k) and 403(b) plans are a critical source of savings for millions of workers at all ages and income levels, the report found. When paired with Social Security benefits, the defined contribution system has helped improve U.S. retirement prospects over time.

The organizations found that almost 80 percent of full-time workers have access to employer-sponsored retirement plans, and more than 80 percent of workers with access to plans at work participate. They believe that with further refinements, coverage could be increased to benefit other workers as well.