1991

7.7

2015

6.9

2009

7.4

2013

8.6

2001

8.1

2004

8.0

2006

7.5

2014

7.6

2010

8.1

2003

8.2

2011

8.5

2004

8.2

2005

8.1

1997

8.4

2001

8.0

2013

6.9

2015

8.3

2012

6.6

1966

8.0

2003

7.5