2002

6.8

2008

6.3

2006

4.9

1990

7.3

1981

7.0

1975

4.0

2000

5.8

1988

5.4

2009

8.0

1991

3.5

2001

5.3

2011

3.7

2010

9.0

1999

5.5

1994

6.0

2008

5.8

1967

6.8

2009

3.8

2010

5.3

2008

5.6