Steve Murphy swears he has nothing against his parents.

But at age 27, Mr. Murphy, who has his own financial planning business, does not feel like he should still be living in his childhood home in Massapequa, Long Island.

“I think I’m pushing the limit, to be honest with you,” he said. “But you almost become complacent. You almost think it’s the norm.”

In a sense, it is. According to a new report from the Regional Plan Association, an urban research and policy group, 55 percent of all 20- to 34-year-olds on Long Island still live with their parents, which is up 11 percent in a decade and appears to be one of the highest rates in the country.

But while some may actively choose to sleep in full view of their teenage posters and trophies, most are there because there are few other places they can go.