WOOSTER, Ohio — Even at age 70, Ron Hustwit has no itch to retire.

He has taught philosophy full time at the College of Wooster in Wooster, Ohio, for 46 years and, unlike many friends and colleagues who chose to retire long ago, he still enjoys going to work.

“I don't have any days when I say I have to put in another day at the office,” he said.

Hustwit, who lives across the street from the campus, is one of a growing number of seniors who are opting to remain in the work force.

The U.S. Census Bureau reported that the percentage of people 65 or older still working rose from 12.1 percent in 1990 to 16.1 percent in 2010, driven largely by women.

And the bureau's latest American Community Survey report shows even higher numbers. The figure was 19 percent nationwide.

The reasons are varied. Some seniors are doing it strictly for the money, knowing they don't have enough saved to retire or they are worried that they'll outlive their savings. Others, like Hustwit, know they would miss the social interaction at work or they have no burning desire to take up a hobby such as golf or traveling.

Then there's a less obvious reason: A growth in service and office jobs doesn't require major physical labor, allowing seniors to work longer.

“People are living longer, and they are healthier,” said Paul Magnus, vice president for work force development at Mature Services, an Akron, Ohio, nonprofit that helps older workers find jobs. “To look at age 65 and think you have two decades left of active lifestyle, work is part of it.”

The topic is especially relevant given 85-year-old Pope Benedict XVI's decision to retire, said Harvey Sterns, director at the Institute for Life-Span Development and Gerontology at the University of Akron and author of the book “Working Longer.”

It's the first papal resignation in almost 600 years.

Retiring at a younger age is a relatively new concept, experienced only by about the last two generations, he said. Before, most people worked until they died.

Sterns, who is 70 and still works full time, grew up in a family that owned a department store.

“We used to say in the Sterns family: 'You die in the aisle making the sale. But you first finish the sale,'” he said.

While the trend of more seniors working is expected to continue, Sterns noted that many people have no intention of working longer than they have to.

“We have to remember that a lot of people don't like their work,” he said. “Work is only there to get money to do the things you really want to do.”

Why work?

During a recent jobs program at Mature Services, the Beacon Journal newspaper asked people — not all were past 65 — why they wanted to return to work. The No. 1 answer involved money.

Some said they or their friends didn't plan well enough for retirement. Or, because of the recession, they started raising their grandchildren and needed the income.

Another popular reason was social. They don't want to sit at home alone. Some said people who live longer seem to have two things in common: They work as long as they can, and they eat oatmeal daily.

“I like to keep working because it's good for my brain,” said Victoria Anania of Akron. Anania, who would only say that she's over 65, worked for years as a nurse and now wants to work again.

“Age is just a number anyway. It's how you feel inside,” she said.

Rose Schaffer, 85, of Norton, Ohio, works part time at Akron Monument & Granite. Each Monday, she comes into the office for several hours to keep the books, prepare invoices and answer the phone.

On other days, she works at home, spending an hour or so reading newspaper obituaries and sending condolence letters to potential customers.

“Work is good therapy,” she said. “I think that's what has kept me young.”

Schaffer retired once, in 2000.

“I stayed home for about six months, and I couldn't stand it,” she said.

Women make up a rising percentage of seniors who work.

Sterns, the gerontology professor, isn't surprised. Women often enjoy the social interaction at work more than men, or they are forced back into the work force after a divorce or staying home to raise a family, he said.

They also live longer than men. The life expectancy for women in the U.S. is 81, compared with 76 for men.