Arizona schools have been found to be underfunded and low performing, according to a new study released by Education Week.

Education Week’s Quality Counts report studied factors gauging performance in chances for education success, school finance and K-12 achievement. Arizona is falling behind in all three categories.

Overall, Arizona was rated a D-plus state, maintaining that score since 2015. Only six states performed worse than Arizona: Idaho, Louisiana, Mississippi, Nevada, New Mexico and Oklahoma. The national average was a C.

For per-pupil spending, Arizona’s education system came in at 50th out of 50 states plus Washington, D.C., and earned a D-minus for school finances. However, Arizona ranked 27th for spending equity across school districts, with a spending gap between the highest and lowest spending districts at only $2,961. The national average gap is $4,776.

Education Week’s Quality Counts report has been done for 21 years. This year’s report is based on 2015 spending figures, and looks at data points like family income, parent education, preschool/kindergarten enrollment, elementary school reading scores, middle school math scores, graduation rates and post-graduation employment.