1981

6.6

1980

5.0

1974

7.7

1984

5.8

1989

5.2

1990

4.0

1979

6.0

1976

7.0

1972

7.4

1974

7.0

1984

5.6

1977

5.6

1979

5.0

1978

5.0

1979

3.5