HACKENSACK, N.J. — You know what ticks off Mary Planten?
She'll be minding her own beeswax when she happens upon a Holland Christian Home neighbor in the company of a visitor.
"Tell 'em how old you are, Mary!" the neighbor invariably asks Planten, who is 107.
"It's as if I'm a 3-year-old!" grouses Planten, who doesn't make a to-do about her age and can't even find the congratulatory letter from the White House.
Planten lives independently at the North Haledon, N.J., retirement home. She is engaging and witty and loves email and puzzles. She gets around fine with a walker. Except for aching joints, there's nothing wrong with her.
"Amazed by myself?" Planten says. "Oh, I don't know. I received good genes to start with."
Centenarians are objects of wonder — and there are many more of them to behold. Because of strides in medical care and health practices, their ranks have increased 65.8 percent since 1980, while the nation's population as a whole rose 36.3 percent. The 2010 census counted 53,364 people age 100 and older in the United States. Projections point to a million centenarian Americans well before the end of the 21st century.
Daughters of Miriam Center in Clifton, N.J., has a concentration of centenarians — 12 of the nearly 500 nursing home residents and apartment dwellers.
"Turning 100 is still an accomplishment, don't get me wrong," says Karen Speizer, the facility's marketing director. "But it's not as remarkable as it once was."
Agnes Fenton of Englewood, N.J., is 145 days older than Planten. She'll be 108 on Aug. 1.
"I don't feel no different now than when I was 15," says Fenton, who has lived in the same small house since the 1950s. "I shouldn't say 15. I should say 22. That's when I had my first drink of Johnnie Walker Black."
Fenton still cooks her own meals and is checked on by relatives, neighbors and the Fire Department. She says her daily doses of whiskey and Miller High Life have gotten her this far. She also credits her mother's living to 93 and an even higher power.
"God did it," she says. "When I was born, I was born to die. There was just no date set."
Fenton, whose only health complaint is arthritis in her right hand, is helping scientists understand the genetic and environmental factors that contribute to exceptional advanced age. She's one of the 80 people over age 105 enrolled in the New England Centenarian Study, a project of the Boston University School of Medicine. Fenton displays two characteristics researchers typically see in centenarians: She was never overweight and has kept stress at bay.
"She's pretty low key," observes her 64-year-old nephew, Lamont Saunders. "Very rarely have I seen her get upset."
Fenton hopes to visit her Mississippi hometown this spring and has set a goal of reaching 109. Told that the longest confirmed human lifespan is 122 years, she remarks: "Oh, my God, I don't want to make it that far. I wouldn't be able to get out of the house."
It's easy to believe that spunky Agnes Fenton will be blowing out 109 candles on her birthday cake 17 months from now. So she's got to be the oldest person in New Jersey, right?
Nope. George Eberhardt of Chester is 10 months older. He'll be 109 on Sept. 29. Eberhardt, also a participant in the New England Centenarian Study, "is still walking, talking and eating" and enjoys listening to classical music, reports his 89-year-old wife, Marie.
So is he the oldest New Jerseyan?
Maybe. Maybe not.
Yet as amazing as 108-year-old George Eberhardt, 107-year-old Agnes Fenton and 107-year-old Mary Planten are, it takes a relative youngster — Astrid Thoenig, 103, of Parsippany — to unlock what may be the real secret to a superlong life: staying busy.
For more than 30 years, Thoenig has worked at her son John Thornton's insurance agency. A whiz with a calculator, she handles the accounts payable and accounts receivable.
Don't mention retirement to her.
"Most people attribute her longevity to her work and devotion to work," her son says. "It gives her a reason to get up in the morning, get dressed — and come to the office."