2006

4.1

2004

4.7

2011

4.9

2007

5.0

1999

6.1

2012

5.1

1998

6.6

2011

2.9

1978

6.9

2013

7.4

2005

6.2

2014

5.3

2005

5.0

2014

6.8

2011

7.3

2016

7.9

1990

7.7

2010

6.6

2017

8.1

2009

7.3