1991

7.4

2007

7.8

2004

4.5

1984

8.1

1951

7.6

2000

7.1

1996

7.0

2006

7.7

2002

6.3

2008

6.6

1997

5.7

1991

6.8

2007

6.3

1973

6.0

2004

4.7

2008

6.9

2008

6.6

2023

6.2

1996

6.4

2022

6.8