2007

6.3

2014

6.2

2010

6.6

2017

6.5

2018

7.6

2016

8.2

2001

6.7

2008

6.2

2010

6.4

2009

5.3

2012

6.9

2010

6.8

1989

7.8

2006

6.2

1999

6.3

1977

6.3

2015

6.7

2004

7.3

2018

5.9

2008

7.6