CHICAGO (AP) – Illinois data shows almost one in four public school teachers in the state miss 10-plus days of the school year.

The Chicago Tribune reports the annual Illinois Report Card, a compilation of data that paints a broad picture of schools, shows that 23.5 percent of public school teachers are absent more than 10 days in the school year. The teacher absence rates ranged widely at some 3,600 public schools, with nearly 1,600 schools, mostly in the Chicago area, faring worse than the state average.

Some administrators and teacher union officials have questioned whether the figures are accurate and how they were calculated.

U.S. Department of Education cites research that says children don’t do as well when teachers are absent more than 10 days in a school year. Districts also end up spending money to pay substitutes.