2013

6.5

2006

7.0

2001

6.7

1999

5.8

2011

5.7

1996

8.1

2000

5.1

1991

5.3

1985

7.1

1997

9.3

2016

6.0

2010

6.0

2004

6.7

1998

7.5

1981

7.3

2014

5.7

2009

5.7

2016

4.0

2002

7.1

2006

6.8