The Iowa Department of Education says the high school graduation rate continues to show long-term progress despite a slight dip last year. Data shows 91 percent of students in Iowa's class of 2017 graduated within four years. That's down three-tenths of a percent from 2016. However, Iowa's four-year graduation rate has climbed nearly three-percent since 2011. Graduation rates for African-American students have increased four years in a row and by more than nine-percent since 2011, though it remains 10.5f percent behind the rate for white students.