2015

6.7

2010

6.6

2011

7.1

2008

5.1

2003

6.0

1987

5.5

2013

7.3

2010

6.3

2008

7.6

1988

5.8

2001

6.1

1990

6.5

1991

6.9

1985

8.3

1998

7.2

2007

6.0

2014

6.9

2009

6.8

1982

7.5

1991

5.3