2005

8.3

2012

7.4

2004

7.6

2015

7.7

2014

8.4

2009

6.2

1999

7.0

2004

5.8

2011

8.2

2013

7.5

2017

6.5

2018

8.1

1988

7.4

2009

7.4

1997

6.4

1999

6.5

2011

7.2

2011

8.1

2015

6.9

2009

7.7