Washington ? The rolls of America’s oldest old are surging: Nearly 2 million now are 90 or over, nearly triple their numbers of just three decades ago.

It’s not all good news. They’re more likely than the merely elderly to live in poverty and to have disabilities, creating a new challenge to already strained retiree income and health care programs.

First-ever census data on the 90-plus population highlight America’s ever-increasing life spans, which are redefining what it means to be old.

Joined by graying baby boomers, the oldest old are projected to increase from 1.9 million to 8.7 million by midcentury — making up 2 percent of the total U.S. population and one in 10 older Americans. That’s a big change from over a century ago, when fewer than 100,000 people reached 90.

Demographers attribute the increases mostly to better nutrition and advances in medical care. Still, the longer life spans present additional risks for disabilities and chronic conditions such as arthritis, diabetes and Alzheimer’s disease.

“If I get stuck with something I can’t handle, I yell for the kids,” says Betty Mae Gutoski, 85, of Muskegon, Mich., who says she expects to live past 90. After all, her father lived to 98. The colon cancer survivor lives alone and says she is “comfortable,” getting occasional help with yard work from her son and grandson, who live next door.

Gutoski said in a telephone interview that she maintains her health by leading a busy life — driving, grocery shopping once a week, sewing, visiting the senior center, volunteering and meeting her friends for lunch — but she acknowledges having some fears. “My big worry is becoming a burden on my family,” she said.

Richard Suzman, director of behavioral and social research at the National Institute on Aging, which commissioned the report, said cases like Gutoski’s are increasingly common. Personal savings for retirement can sometimes be a problem, he said, if people don’t anticipate a longer life or one with some form of disability.

An Associated Press-LifeGoesStrong.com poll in June found that more than one in four adults expect to live to at least 90, including nearly half of those currently 65 or older.