(CNBC) -- If you have an adult child living at home, you could become an empty nester sooner than you thought.
The number of 18- to 34-year-olds living with parents last year edged down from 2016, according to new data from CoStar Group, a commercial real estate information company in New York.
Last year, 31.5 percent of that age cohort were living with Mom and Dad, down slightly from more than 32 percent in 2016. While still higher than the long-term average of under 28 percent, it's a downward trend the firm expects to continue due to the strength of the job market and overall economy.
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