Despite steady gains in hiring, a falling unemployment rate and other signs of an improving economy, take-home pay for many American workers has effectively fallen since the economic recovery began in 2009, according to a new study by an advocacy group that is to be released on Thursday.

The declines were greatest for the lowest-paid workers in sectors where hiring has been strong — home health care, food preparation and retailing — even though wages were already below average to begin with in those service industries.

“Stagnant wages are a problem for everyone at this point, but the imbalance in the economy has become more pronounced since the recession,” said Irene Tung, a senior policy researcher at the National Employment Law Project and co-author of the study.

Jasmin Almodovar, a home health care aide in Cleveland, knows all about that.

She has worked for the same health care agency since 2003, and for the first four years she received an annual wage increase of 25 cents an hour. But since 2007, her hourly pay has been stuck at $9.50 an hour.