Mantle, Mays, Aaron cumulative OPS 1954-1964.

Career OPS (On Base Plus Slugging):
Mickey Mantle .977    peak: 1.011 1963, 1964
Willie Mays .941    peak: .984 1958
Hank Aaron .928    peak: .947 1963, 1973

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And there's every indication that Mantle's numbers would have been better if he had batted righty exclusively, instead of switch hitting.