1970

7.3

2008

7.0

1987

7.6

2006

6.8

2019

6.4

2001

6.3

2012

5.7

2019

7.4

2013

6.7

1980

7.5

1994

7.4

2017

6.3

2007

7.5

1990

6.9

2009

5.9

2007

6.4

2016

6.5

1956

7.2

1983

5.7

2016

7.0