1976

6.1

1980

6.7

1985

6.9

1984

6.1

1979

7.0

1978

3.2

1971

6.5

1988

6.1

1983

6.8

1982

5.8

1970

4.9

1976

4.3

1977

6.2

1978

3.5

1973

3.5

1984

4.3

1981

7.0

1974

6.2

1971

5.9

1980

6.8

1985

6.6