The College World Series was a straight double-elimination event until 1987. The 1987 College World Series put a stop to it. The Division I tournament started holding preliminary rounds in 1954 to decide the eight CWS teams. The number of teams in the first round of the overall tournament fluctuated from 21 to 32 from 1954 to 1975. When the number of teams increased to 32 in 1976, the number of games per team was reduced from an average of 14 to 12. In 1980, the number of games per team was reduced to 11. In 1981, the format was changed again. Now there were three separate single-elimination tournaments: one for each class. The winners of these classes went on to play for the championship. This system continued through 1986. In 1987, the double-elimination format returned to the series. The 1988 season was the last season that had only three classes. From 1989 to 2015, all seasons have had four classes. Starting with 2016, all seasons will have five classes. The top two classes will be Division I while the other three divisions (Division II, Division III, and Division IV) will have two groups of three schools playing in regional competitions before the winners meet in the final week of the season. There has been one year where there were six teams in the College World Series. That was in 1978 when Oklahoma State, Miami (OH), North Carolina, California, Texas, and Florida all made the trip to Omaha.