2008

6.8

2004

5.6

2007

6.9

2014

5.1

2000

5.7

2006

7.6

1998

7.3

2007

6.5

1992

7.0

1995

7.7

1978

7.5

1995

6.5

2008

5.1

2006

6.4

1984

4.2

2002

6.2

2003

6.2

2006

5.5

2009

3.8

1992

0.0