The state Department of Education says Iowa's graduation rate increased to more than 89 percent, the highest in the nation.
The department reported Wednesday that 89.26 percent of Iowa's class of 2012 graduated, up nearly 1 percentage point from 2011.
Iowa's four-year graduation rate ranks first nationally.
Graduation rates increased in 172 of Iowa's 318 school districts that had high schools.
Of the 10 largest districts, eight saw graduation rates rise. The biggest jump among those districts was in Des Moines, where the rate climbed 3.47 percentage point to 79.15 percent.
Iowa Department of Education Director Jason Glass noted the strong numbers but added that the state needs to ensure graduating students are adequately prepared.
State lawmakers are considering reforms aimed at improving Iowa's public school system.