No statewide initiative has qualified in Nebraska since 2008, but it is likely that the 2014 ballot will have an initiative to raise the minimum wage. See this story, which says that proponents submitted 135,000 signatures. They needed 81,000. There is also a county distribution requirement, which is under attack in a federal lawsuit now pending, Bernbeck v Gale, 8:13cv-228. Thanks to Doug McNeil for the link.