1960

7.8

1957

7.2

2010

6.1

1996

6.7

2009

5.6

2013

7.2

2004

5.1

2008

5.9

2016

5.9

2007

5.7

2012

6.3

2016

7.3

2001

6.2

1968

6.6

2006

5.5

2015

6.0

2012

7.7

2008

6.9

2010

6.3

2018

5.6