1964

7.2

1963

7.4

1957

5.8

1962

6.1

1970

5.7

1961

6.2

1958

6.4

1971

2.8

1965

6.7

1960

5.2

1966

7.1

1962

6.3

1962

6.5

1962

5.9

1971

6.3

1973

6.8

1977

5.7

1960

5.7

1967

6.2

1971

6.8

1967

3.1

1958

6.5