Sweden's most successful period at Eurovision was between 1983 and 1991. The country achieved four top three finishes—two more than it had accumulated in the previous twenty-five years—with two victories among them. The voting system used at Melodifestivalen during most of this period was introduced in 1982. It remained in use intermittently until 1998, later becoming synonymous with the event and the basis for the modern semifinal format. The regional juries narrowed the contenders down to five, giving the contestants the opportunity to perform their songs again in a second round before the juries voted again to find a winner.