1975

7.3

1976

5.7

1973

6.4

1978

7.1

1981

6.8

1986

6.6

1978

2.3

1979

6.7

1972

5.8

1978

3.5

1973

6.4

1984

7.4

1968

6.5

1977

6.3

1969

3.8

1984

7.4

1977

7.7