The director of Wisconsin's elections agency Kevin Kennedy was releasing the estimate on Tuesday. That compares with nearly 20 percent turnout in the 2010 primary when there was a contested Republican primary for governor.
This year, there is a Democratic primary in which former state Commerce secretary and Trek Bicycles executive Mary Burke faces state Rep. Brett Hulsey, of Madison. Hulsey has mounted a longshot bid against Burke, who has the backing of the party and is raising millions to take on Gov. Scott Walker.
There is also a Democratic primary in the attorney general's race with state Rep. Jon Richards facing Jefferson County District Attorney Susan Happ and Dane County District Attorney Ismael Ozanne.