The ranks of the so-called working poor have grown even as the nation has created new jobs for 27 consecutive months and is showing other signs of shaking off the worst effects of the recession.

“Although many people are returning to work, they are often taking jobs with lower wages and less job security, compared with the middle class jobs they held before the downturn,” said a report released Tuesday by the Working Poor Families Project, a national initiative aimed at fostering state policies to help low-income working families.

With the nation’s economy in recovery, the report said, more than 70 percent of low-income families and half of all poor families were working by 2011, the report said. The problem is they did not earn enough to cover their basic living expenses.

“We’re not on a good trajectory,” said Brandon Roberts, who manages the Working Poor Families Project. “The overall number of low-income working families is increasing despite the recovery.”

Analyzing 2011 data from the Census Bureau’s American Community Survey, the report said that 32 percent of working families earned salaries that put them below double the poverty threshold, which was $45,622 for a family of four. That percentage has crept up from 28 percent in 2007, the year the recession began.

And 37 percent of the nation’s children — 23.5 million — were part of working poor families in 2011, the report said, up from 33 percent in 2007.

Nearly three in five low-income working families were headed by at least one minority parent, even though minorities headed 42 percent of all working families.

The growth in the ranks of the working poor coincides with continued growth in income inequality. Many of the occupations experiencing the fastest job growth during the recovery also pay poorly. Among them are retail jobs, food preparation, clerical work and customer assistance.

At the same time, researchers have found that many jobs that do not require much in the way of educational credentials but pay relatively well have lagged in the recovery.