2011

4.9

2012

5.1

2005

6.2

2013

7.3

1999

6.1

2004

4.7

1998

6.6

2005

6.2

2003

6.4

1994

7.9

2005

5.0

2014

6.8

2011

7.3

2016

7.9

2009

7.2

2011

7.3

1990

7.7

2017

8.1

2009

7.3

2018

6.8