1963

5.7

1956

6.6

1975

5.2

1981

6.4

1971

7.5

1976

6.6

1979

5.1

1987

5.0

1980

6.6

1966

7.2

1967

7.0

1964

8.0

1966

6.1

1968

6.7

1960

5.0

1957

5.8