"We predict that the turnout was 83.90 percent," Rizka Halida, senior researcher of Indikator Politik, said here on Wednesday.
The pollster conducted a quick count of voting results at 2,976 polling stations (TPS) spread proportionally across the country, she said.
It selected TPS samples by using a stratified systematic random sampling method.
Based on the quick count results, the Joko Widodo (Jokowi)-Ma'ruf Amin pair collected 54.07 percent of votes and contender Prabowo Subianto-Sandiaga Uno collected 45.93 percent, she said.
Indikator Politik predicted that Jokowi would win the elections.
Indonesia held simultaneous legislative and presidential elections on April 17, considered to be the largest single-day democratic election in the world.
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