Question: Sacramento Mather Airport is located on the site of a former air force base, located 12 mi east of Sacramento, on the south side of U.S. Route 50 in Sacramento County, California, which was closed in what year?
{'answer': '1993', 'supporting_facts': [['Sacramento Mather Airport', 0], ['Sacramento Mather Airport', 1], ['Mather Air Force Base', 0], ['Mather Air Force Base', 1]]}