1978

7.1

2014

6.6

2013

10.0

2007

5.6

1972

6.3

1998

5.9

1982

6.1

2014

5.5

2008

5.8

2009

6.7

2006

5.6

2009

5.2

2009

6.0

2016

7.7

2004

6.0

2001

4.7

1997

6.9

1995

6.7

1986

6.5

2002

5.8