The statewide high school graduation rate surpassed 90 percent last year, according to data released Wednesday by the Iowa Department of Education. The figures, which detail how many students graduate high school within four years, show a slight increase statewide, from 89.7 percent in 2013 to 90.5 percent in 2014. Cedar Rapids schools had the largest increase in four-year graduation rate among the state's 10 largest school districts.