1988

6.2

2004

6.7

2010

7.3

2007

6.0

2016

6.3

1983

5.9

2001

6.2

2004

7.0

2015

7.1

2014

6.4

2007

6.9

2010

6.2

2017

7.8

2006

5.9

1983

4.7

2004

6.1

2007

7.3

2015

6.8

2014

6.6

2001

6.1