2008

6.7

2014

6.9

2009

7.2

2011

7.5

2006

8.1

2006

7.8

2006

7.4

2005

6.8

2001

8.0

2004

7.4

1973

7.0

1998

8.2

2010

6.9

2002

7.0

2015

7.9

1983

8.0

1987

5.5

2000

7.6

2008

7.7

2004

8.1