1970

5.5

2005

7.0

1998

6.4

1999

8.5

2003

7.2

1964

7.1

1976

6.4

2002

7.6

2004

7.4

2006

7.5

2005

4.6

2001

6.4

2001

6.6

2007

7.5

2001

5.3

2004

5.3

2020

6.9

2008

7.2

2007

6.0

2023

6.2