1989

7.1

2007

5.8

2001

7.8

2014

8.5

2018

7.5

2009

7.6

2016

7.9

2016

7.3

2003

7.8

2016

6.8

1998

8.1

1994

8.7

2012

7.2

2015

7.3

1987

7.3

2014

8.4

2015

7.5

2016

7.6

2013

6.8

2012

6.4