1976

7.3

1981

5.4

1965

4.5

1968

6.9

1967

7.1

1970

7.8

1978

6.2

1972

5.5

1975

7.2

1964

8.0

1977

6.3

1962

7.0

1978

6.7

1969

6.5

1971

2.9