1940

8.1

1929

6.1

1973

7.1

1968

7.3

2002

7.0

2006

6.4

2003

6.0

2000

7.6

1987

7.3

2002

7.0

2005

7.8

1968

7.4

1997

6.6

1993

7.2

2004

6.0

2007

6.2

2007

5.0

2004

7.9

2008

5.5

2008

6.6