1975

3.3

1981

7.0

1999

5.5

1986

0.0

2000

5.8

2007

6.3

2009

7.9

2006

5.0

1990

7.3

2002

6.8

2001

5.3

2011

3.4

2012

5.5

1994

6.0

2010

5.3

1967

6.7

2008

5.8

2009

3.4

2010

9.0

2008

6.3