Mantle, Mays, Aaron: BA percent above league.

Mickey Mantle - never negative; high 39.3%
Willie Mays - high 30%
Hank Aaron - high 37%


Click link to view detailed data.  Click tab "BA % above L by Year".

baseball-reference.com definition of lgBA: a league average (non-pitcher) would have had in the same park(s).

lgBA of Mays and Aaron differs for common National League seasons: 1954-1973.  lgBA appears to be by team, not player.  Have requested clarification from baseball-reference.com.  Mays split 1972 between two teams and the total lgBA assigned to Mays appears to be a weighted number between the two teams based on at bats for Mays with each team.

Year  Aaron Mays Mantle
1951 1.86% 1.52%
1952 -10.27% 22.92%
1953                11.32%
1954 4.87% 25.45% 14.50%
1955 20.31% 19.48% 15.47%
1956 27.63% 12.55% 33.71%
1957 23.85% 23.79% 39.31%
1958 25.38% 29.96% 18.29%
1959 37.07% 17.23% 11.33%
1960 14.96% 24.61% 6.59%
1961 25.77% 16.23% 22.87%
1962 21.43% 13.01% 22.99%
1963 26.09% 24.11% 23.62%
1964 24.24% 11.28% 17.44%
1965 23.26% 20.99% 2.00%
1966 4.10% 7.06% 19.01%
1967 19.46% 1.94% 2.94%
1968 13.44% 14.23% 2.16%
1969 14.94% 9.69%
1970 9.16% 9.40%
1971 22.47% 4.63%
1972 -0.75% -1.57%
1973 10.66% -18.85%
1974 0.37%
1975 -9.30%
1976 -9.84%
min -9.84% -18.85% 2.00%
max 37.07% 29.96% 39.31%
ave 15.20% 13.26% 16.82%
StDev 12.28% 11.32% 10.98%
name Aaron Mays Mantle