(CNN) -- Chilean voters cast ballots in a presidential election on Sunday, but no candidate secured enough votes to declare victory. The South American country is set to hold a runoff election December 15. Socialist Michelle Bachelet, who was Chile's president from 2006 to 2010, will face off against Evelyn Matthei of the conservative Independent Democratic Union party. Chile's constitution requires a candidate to garner more than 50% of votes to win the presidential election. Bachelet had won 46.8% of votes with more than 92% of votes counted, elections officials said Sunday night. Matthei had garnered 25.1% of votes. READ MORE: Can Bachelet lead Chile to change? CNN's Elwyn Lopez contributed to this report.
Socialist Michelle Bachelet won a majority of votes, but not enough to win . The South American country will hold a runoff election on December 15 . Bachelet was Chile's president from 2006 to 2010 .