A study released Tuesday found that 35.1% of people with credit records - roughly 77 million - had a debt in collections based on September 2013 records from TransUnion. The debt averaged $5,178.

The study, released by the Urban Institute and Encore Capital Group's Consumer Credit Research Institute, indicates the share of Americans in collections has remained steady even as the U.S. pares down the size of its credit card debt since the official end of the economic slump in the middle of 2009.

Credit card debt has reached its lowest level in more than a decade, according to the American Bankers Association. Just 2.4% of card accounts are overdue by 30 days or more, versus the 15-year average of 3.8%.

This is the first time the Urban Institute calculated the collection figure, but researchers noted that the 35% is basically unchanged from when the Federal Reserve studied the issue in 2004 and found that 36.5% of people with credit reports had debt in collections.

Caroline Ratcliffe, senior fellow at the Urban Institute and author of the report, said stagnant income is the main reason why large parts of the country are struggling to repay debt.

Wages barely have kept pace with inflation during the five-year economic recovery, according to Labor Department figures. A separate measure by Wells Fargo found that after-tax income fell for the bottom 20% of earners during the same period.

The delinquent debt is concentrated in Southern and Western states. Texas cities have a large share of their populations being reported to collection agencies: Dallas (44.3%); El Paso (44.4%), Houston (43.7%), McAllen (51.7%) and San Antonio (44.5%).

Almost half of Las Vegas residents, many greatly impacted by the housing bust that sparked the recession, have debt in collections. Other Southern cities have a disproportionate number of their people facing debt collectors, including Orlando and Jacksonville, Fla.; Memphis, Tenn.; Columbia, S.C.; and Jackson, Miss.

Other cities have populations that have largely managed to repay their bills on time. Just 20.1% of Minneapolis residents have debts in collection. Boston, Honolulu and San Jose, Calif., are also on the low end.

According to a separate study published this year by the Federal Reserve's Philadelphia bank branch, the collection industry employs 140,000 people who recover $50 billion each year.

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