Irene Olsen, 95, who formerly ran a hat shop, oversees the travel department at the Millford, Conn., senior center.
STAMFORD, Conn. - At 92, Pete Perillo still has a workday routine. He says a prayer and then heads off in uniform to guard the city courthouse.
"In the morning, I talk to St. Anthony and I come in," Mr. Perillo said. "I come in every day. These people, they keep me alive."
He is a judicial marshal in the civil division of Stamford Superior Court. He carries no gun.
He is one of a growing number for whom retirement age has lost its meaning. They're staying on the job longer, some for personal satisfaction, others out of necessity.
Some are working into their 90s and beyond: In Maryland, Grace Wiles, 97, puts in about 25 hours a week at a shoe repair shop. In Nebraska, Sally Gordon, who is 98, is the legislature's assistant sergeant at arms.
They're all younger than Waldo McBurney, 104, a beekeeper from Kansas recently declared to be America's oldest worker.
Pete Perillo, 92, is a marshal in Stamford, Conn.
About 6.4 percent of Americans 75 or older, or slightly more than 1 million, were employed last year. That's up from 4.7 percent, or 634,000, a decade earlier, according to the U.S. Department of Labor.
About 3.4 percent of Americans 80 or older, or 318,000, were in the work force last year, up from 2.7 percent, or 188,000, a decade earlier, officials said.
"For the first time in history, four generations are working together," said Melanie Holmes, vice president of corporate affairs for Manpower Inc., an employment services company.
With the first wave of Baby Boomers reaching the traditional retirement age, Manpower has urged companies to start thinking about ways to retain and recruit older workers, through flexible scheduling, for example. This will help them fill positions as the labor pool shrinks.
Companies need to extend their diversity training to include age as well as race and gender, Ms. Holmes said.
Older workers often bring experience and a strong work ethic, but may have a different style of work: They may be better at face-to-face contact than with electronic communications and may adhere more strictly to company rules, Manpower officials said.
Some companies are reluctant to hire older workers. A survey last year by the employment firm found that 24 percent of employers viewed expectations for higher salary or stature as one of the top roadblocks to hiring older workers, and 21 percent cited health-care costs.
Still, after decades of decline, the number of workers 55 and older began to rise about a decade ago, and that trend has accelerated since 2000, labor officials said.
Experts cite several factors for the growth, including people living longer and the Senior Citizens Freedom to Work Act in 2000, which allowed workers ages 65 through 69 to make as much money as they want without losing Social Security benefits.
Other reasons include the gradual increase, to 67, in the age for receiving full So-cial Security benefits and a decline in traditional pensions and retiree health benefits.
The number of older workers is likely to continue to rise as Americans live longer and are unable to make ends meet on Social Security and savings, said Alicia Munnell, director of the Center for Retirement Research at Boston College. "It's a concern to me they will end up having to work," she said.
Irene Olsen, 95, puts in 20 hours a week at a senior center in Milford, Conn., to pay rising taxes and utility rates.
Ms. Olsen, who formerly ran a hat shop in Milford, oversees the travel department at the senior center. She spoke out recently against a property revaluation.
"They doubled the value of my house, which doubles my taxes," she said. "That's why I work. I can't live on my Social Security and own a house."
Ms. Olsen, whose husband died about 20 years ago, drives to work but worries she'll lose her license if she has an accident. But working, she said, "seems normal to me. I've worked all my life."
She's not out of place at the senior center. The tap dance instructor is 90, and the director of the band and the bowling league, Art White, is 95.
Mary Steinmetz, the center's program director, said of Mr. White, "I found him in his office standing on a stool fixing something. He doesn't know why we buy new things when things can be fixed. He always thinks there's a little more life left in everything."
Ms. Steinmetz said the older workers are part of a generation that believes in hard work. They also want to remain independent.
Ms. Gordon, the assistant sergeant at arms in Nebraska, said she works both because she enjoys it and because it pay the bills.
"I like to meet the public," she said. "My house needs a lot of work. Everything is expensive. Medication is out of sight. I don't want to rely on anyone else."