Like many adults in their 30s accustomed to their independence, Tasha Hart had no intention of staying long when she moved into her parents’ house in Newport News, Va., after separating from her husband.

But two years later, she and her two children are still there — and will be for the foreseeable future, although perhaps not “for life,” as her mother predicts, hopefully.

“I came home once before, for six months when I was 25 and trying to find myself,” said Hart, 36. “My friends looked at me like I was from a different planet. It was almost taboo to move back in with your parents. But now people say with the economy the way it is, they wish they could do that, too.”

Hart is part of a phenomenon that began slowly more than three decades ago, accelerated during the recession and has continued into an uneven recovery. Adults 25 to 34 are driving a rise in multi-generational households, according to a report the Pew Research Center released Thursday.

The study concludes that almost one in four young adults in that age group are living in households with several generations under one roof. The vast majority have moved in with their parents, while others are living with grandparents, aunts or uncles.

It is now more common for young adults to live with multiple generations of relatives than it is for those 85 or older, traditionally the group most likely to live with family members.

Overall, 57 million Americans — 18 percent of the population — lived in multi-generational families in 2012, double the number in 1980. There are almost as many young adults 25 to 34 living in these families than there are people under 18.

The growth reflects a more profound and historic change than the rise in adults younger than 25 who could not find jobs during the recession and temporarily moved back home.

The increase in the age group just above them is a striking reversal of a pattern that held through most of the 20th century, when each year registered a decline in multi-generational living. The turning point came in the 1980s, and the number has grown every year since.

Richard Fry, an economist who co-authored the Pew report, points to several factors. The nation has experienced a wave of recent immigrants who are more likely than native-born Americans to live in multi-generational homes. According to the report, 10 percent of households headed by someone born in this country are multi-generational, compared with 16 percent of foreign-born households.

There have been behavioral changes, too. Young adults are marrying later — 29 for men and 27 for women, according to the census, four to five years older than was typical in 1980. Married couples are more likely than single people to live on their own.

A slow economic recovery has played a bigger role than demographics in recent years.

“The multi-generation living arrangement serves a private safety net,” Fry said. “Some of this increase is clearly driven by a less-than-stellar job market.”

Donna Butts, executive director of the advocacy group Generations United, said attitudes toward multi-generational living have changed as it has become more common. In a survey of multi-generational families a few years ago, the group found that many families that came together because of need decided to stay together by choice.

“Previous generations were so much about rebellion and making your own identity,” she said. “Now, parents and children have different relationships. They find they’re liking each other and like to be together.”

Hart said she thought she would stay for a few months, at most, when she moved from Northern Virginia to her parents’ home in 2012. Then a heart condition suddenly flared, requiring surgery. Her mother was there to nurse her through her convalescence and take videos of her daughter heading to her first day of kindergarten, which Hart missed because of the surgery.

“My parents have been pillars to lean on as I’ve dealt with health and finance issues,” she said.

Hart doesn’t want to have to lean on them forever, though.

“I want to move out,” she said. “I thought I’d save money to pay a year’s worth of rent, so I can be in a position to be self-sufficient again. My goal is to be just 10 minutes away. I don’t want to be too far again.”