1976

7.4

1980

6.8

1970

7.5

1952

7.7

1985

7.2

1953

7.4

1968

9.0

1973

7.3

1962

7.8

1987

6.3

1955

6.5

1985

5.5

1988

5.6

1972

5.7

2015

6.9

1973

3.0

1950

7.3

1938

3.0

1948

6.2

1956

6.9