1963

5.9

1988

5.5

1985

6.6

1984

5.2

1983

6.7

1980

5.1

1973

6.9

1979

5.0

1971

6.5

1981

6.0

1982

7.3

1957

7.6

1967

5.1

1970

6.3

1987

4.3