Washington ? The number of Americans 65 and older either working or looking for jobs has grown by 50 percent since 1980, the Census Bureau said Tuesday.

Experts said it was due to people living longer and wanting to work, as well as concerns that retirement savings were being eaten up by stock market losses and that Social Security and other benefits wouldn’t cover senior citizens’ needs.

In 1980, about 3 million people — 12.6 percent of the 24.2 million residents 65 and older — were in the labor force. The share of older workers declined to 11.9 percent in 1990, but it has risen steadily since then, according to census data.

By March 2002, the number of older people with jobs or seeking one was 4.5 million — 13.2 percent of the 65-and-over population.

With the economy stumbling since then, that number probably is higher now, said Edward Coyle, executive director of the Alliance for Retired Americans.

“People are more nervous now than they were a year ago,” Coyle said. “You have lots of folks approaching retirement age, scratching their heads and wondering if they can do it.”

Other findings

The latest Census Bureau data comes from a nationwide survey of 70,000 homes in March 2002 that covered a range of socioeconomic characteristics, from income to education. Among other findings:

l About one-third of those 65 and older live alone. That’s virtually unchanged since 1980.

l Roughly one in 10 live in poverty.

l More than eight of 10 homes headed by an older person are owned, a high since 1982 but in line with the overall growth of homeownership in the United States.

l About 18 percent of men 65 and older were in the labor force, almost twice the rate for women.

While some seniors have simply delayed retirement and others have taken the opportunity to open small businesses, many were forced back into the labor market. Most of these people took low-level administrative or service jobs, which were plentiful during the late 1990s, said Jared Bernstein, an economist with Economic Policy Institute.

More than 15 percent of 65-and-older employees worked in sales in 2002, the largest share of any occupation. It was followed by professional fields, like architecture or medicine, and clerical jobs.

Congress voted in 1983 to raise the retirement age from 65 to 67 by 2027, a change which might have encouraged some older workers in the 1980s and 1990s to put off retirement even though the change didn’t immediately affect them, said John Haaga, a demographer with the Population Reference Bureau, a research group.

Other reasons cited by Haaga: People are living longer, healthier lives and feel like working longer, and an increasing number of women have returned to work after raising children.

But concerns about the solvency of Social Security, rising health care costs and the faltering economy have played roles too, Bernstein said.

In March, government trustees said Medicare — the health care program for seniors — would be insolvent by 2026, four years earlier than previously predicted, as the massive Baby Boom generation hits retirement age. Social Security’s projected insolvency date is 2042.

The stock market swoon of recent years put a dent in many workers’ retirement reserves as well, forcing some to head back to work, Bernstein said.

“Fluctuations in a stock market might not mean much to a younger person, but for someone retiring, cashing out in a down market is a pretty unfortunate thing to do,” he said.