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?
Sentence (from "Mather Air Force Base"): It was located 12 mi east of Sacramento, on the south side of U.S. Route 50 in Sacramento County, California.
Relevant evidence: Yes