Question: When did the conference the UNLV Runnin' Rebels are a member of begin operations?
{'answer': 'July 1999', 'supporting_facts': [["1989–90 UNLV Runnin' Rebels basketball team", 0], ["1989–90 UNLV Runnin' Rebels basketball team", 1], ['Mountain West Conference', 0], ['Mountain West Conference', 1]]}