Gretchen Harris likes the small brick house she bought in Norman, Okla., 36 years ago. She’s fond of her neighbors and the magnolia tree she planted in the front yard. And having a single-story residence proved helpful after knee replacement surgery last summer.

“It’s always been a good size for me,” she said.

But Harris, 72, a retired attorney, has grappled with assorted health problems — heart disease, non- Hodgkin’s lymphoma, osteoporosis, rheumatoid arthritis — and takes a long list of prescription drugs.

Though she feels well enough to hear cases a few days a month as a state administrative law judge and to stay involved in educational and church activities, she worries about the future.

“It weighs on my mind some,” she said. Divorced, childless and without family nearby, “I am going to need some long-term support, independent or assisted living, rather than just living by myself.”

But will she be able to afford it on her income, $4,600 a month from a state pension and Social Security? Harris has no retirement savings and still pays a mortgage on her house, refinanced several times.

She might be able to swing $3,425 for a one-bedroom apartment in assisted living, which an annual survey by Genworth, a financial company, says is the current Oklahoma state median. But that’s projected to hit $4,600 in 10 years; one assisted-living facility in Norman is already charging $4,260 and up.

Even if she sold her house, Harris calculates, she would fall short. “It’s the middle-class bind,” she said. Too much money to qualify for Medicaid or subsidized housing but not enough to pay for long-term care, an industry that has primarily pursued the well-off.

A recent analysis in Health Affairs, pointedly titled “The Forgotten Middle,” investigated how many middle-income seniors will be caught in that bind. The numbers were grim.

Using data from the national Health and Retirement Study, including personal income and assets and health status, the researchers defined the middle- income cohort as Americans from the 41st to the 80th percentile in terms of financial resources.

In 2029, for people 75 to 84 (ages when they’re likely to need long-term care), that would mean access to about $25,000 to $74,000 a year in current dollars. Over age 85 the middle-income category extends to $95,000.

About 14.4 million people will fall into the middle-income category, almost double the current number. Sixty percent will need canes, walkers or wheelchairs to remain mobile, the analysis estimated, and 20% will need extensive help with the so-called activities of daily living, such as bathing and dressing.

They’re a better-educated and more diverse group of older adults than in the past, less likely to experience poverty. Still, most will be unable to afford assisted living, the authors found.

A decade hence, 80% of middle- income seniors will have less than $60,000 a year in income and assets, not including equity in their homes. Yet the estimated cost of assisted living plus out-of-pocket medical expenses will hit $62,000, by the team’s conservative estimate.

“This group gets ignored and underserved in today’s long-term care market, and it’s a problem that’s going to explode over the next 20 years,” said Caroline Pearson, a health researcher at NORC (formerly the National Opinion Research Center) at the University of Chicago and lead author of the study. “When you see the numbers, it’s sobering.”

Depending on how one defines the need, half to two-thirds of older Americans will eventually require long-term care.

Moreover, today’s middle-income older adults have more debt and less savings than earlier cohorts. They’re less likely to receive pensions and have smaller families to turn to for unpaid care.

“A lot of us are going to get stuck in this middle, and it’s pretty scary,” said David Grabowski, a health policy researcher at the Harvard Medical School and the new study’s senior author.

As it happens, the same week the research was published in April, the federal government issued its annual report on Medicare and Social Security solvency. Next year Social Security’s costs will start exceeding its income; the program is projected to deplete its reserves in 16 years. Medicare will deplete its hospital fund in just seven years.

That doesn’t mean either program will evaporate, but benefits will decline if Congress doesn’t take action — as it always has — to shore up financing.

“It’s hard to imagine that Congress wouldn’t step up to make sure they remain viable for future generations,” said Tricia Neuman, director of the Kaiser Family Foundation’s Medicare policy program.

“At the same time, there are tough choices to make, some of which could make long-term care harder to afford.” An example: shifting additional costs to Medicare beneficiaries.

The United States, unlike many Western democracies, has never created a broad public program covering long-term care. Medicare pays for doctors, hospitals, drugs and short-term rehab after hospitalization — not for independent or assisted living.

That could change one day — imagine a new Medicare Part LTC — but “that will be incredibly difficult to achieve politically,” Pearson said.

14.4 million

Number of people ages 75 or older expected to fall into the middle-income category by 2029

60%

Will need canes, walkers or wheelchairs to remain mobile

20%

Will need extensive help with the so-called activities of daily living, such as bathing and dressing