1972

7.8

1968

9.0

1983

8.5

2007

7.1

2005

8.3

2018

7.4

2016

7.0

2017

6.1

2008

7.9

2015

7.6

2008

7.8

2016

7.3

2016

6.9

2002

8.4

2014

7.5

2003

7.9

2015

6.7

2016

7.1

2015

7.3

2008

7.7