INDIANAPOLIS (AP) — About 20 percent of Indiana’s registered voters cast ballots in last month’s midterm primary.

That’s according to the Indiana Secretary of State’s office, which released figures Thursday for the May 8 Republican or Democratic primaries.

It’s a significant increase over the 2014 midterm primary turnout, but a shade under 2010’s turnout, which was 21 percent.

One factor likely boosting interest this year — at least on the Republican side — was a contested GOP Senate race won by former state lawmaker Mike Braun. He beat U.S. Reps. Todd Rokita and Luke Messer and now faces Democratic Sen. Joe Donnelly in November.

The state report shows the highest turnout was 57 percent in Jay County. The lowest was in Vanderburgh County, where 10 percent voted.