ATLANTA — Large corporations and trade groups gave at least $217 million to sway the outcome of state ballot measure and referendum campaigns during the 2014 midterm elections, a new study has found. For the most part, they were overwhelmingly successful in defeating proposals that they didn’t like.

Several wealthy individuals joined those businesses and business groups on the list of the top 50 contributors to ballot measures, according to an analysis released Thursday by the nonpartisan Center for Public Integrity.