1997

6.6

1998

6.3

2007

8.1

2008

6.7

2006

6.7

1972

6.5

2006

6.5

2005

5.7

2003

6.8

2004

7.1

2000

6.4

2001

7.0

1993

8.1

2006

4.3

1923

0.0

2008

6.0

1993

6.6

1991

6.6

2008

5.4

1987

7.3