Complex sentence: He improved to 115 in 1990--91 NHL season, setting up Hull's 72 and 86-goal seasons, the latter the third highest in single-season total in NHL history.
Split into simpler sentences: He improved to 115 in 1990--91 NHL season. He helped Hull score 72 and 86 goals those seasons, the latter the third highest in single-season total in NHL history.