In 1989, the first full season with night baseball at Wrigley Field, Don Zimmer's Cubs were led by a core group of veterans in Ryne Sandberg, Rick Sutcliffe and Andre Dawson, who were boosted by a crop of youngsters such as Mark Grace, Shawon Dunston, Greg Maddux, Rookie of the Year Jerome Walton, and Rookie of the Year Runner-Up Dwight Smith. What year was the first full season with night baseball at Wrigley Field?