2008

4.6

2006

4.7

2010

8.4

2013

8.0

2015

7.9

2017

7.6

2018

6.6

2019

8.1

2017

7.2

2004

8.1

1980

8.2

2016

7.0

1979

7.6

1999

6.9

2016

6.7

1994

8.7

2002

6.0

2019

7.2

2014

7.9

2016

7.7