1990

7.3

2002

6.8

2006

5.0

2000

5.8

1981

7.0

2008

6.3

2009

8.0

1991

3.8

1988

5.4

1968

4.7

2001

5.3

2009

3.8

2010

9.0

2008

5.8

1967

6.8

2012

5.5

2011

3.5

2008

5.3

1999

5.5

1986

0.0