1997

8.1

1998

7.4

2005

7.1

2007

6.8

2002

8.5

2014

8.3

1959

5.8

2001

7.6

2005

3.0

2009

7.3

2002

7.3

1976

7.2

2000

7.0

2000

8.0

2018

8.1

2007

8.5

2007

6.7

2004

6.2

2004

6.0

1997

7.1