1990

8.5

1996

9.6

1979

8.0

1977

6.8

1995

7.6

1982

9.0

1980

9.2

1986

9.2

1996

9.7

1977

8.5

1994

6.8

1995

6.5

1989

7.9

1974

6.0

1981

6.3

1976

5.6

1982

7.9

1983

8.1

1987

6.6

1974

5.1

1974

6.9

1993

7.8

1990

7.0