1983

8.2

1994

4.6

2002

5.4

2006

5.9

1985

6.5

1977

7.1

1991

6.4

1998

7.1

1998

5.5

1995

6.5

1999

7.3

2001

6.0

1988

6.3

1990

6.0

1969

7.0

1999

5.7

2023

9.2

1997

7.5

1991

7.3

2008

5.2