1984

7.1

2000

6.0

2006

5.7

2018

6.2

2016

6.7

2010

6.8

2017

6.7

2017

7.8

2007

6.6

2002

4.5

2006

7.0

2010

7.3

2009

5.5

2003

6.3

1955

6.1

2008

7.5

1981

6.9

1996

6.7

1980

5.9

2018

6.6