2004

6.4

2003

6.3

2006

6.4

2003

6.7

1968

4.5

1999

6.5

2000

6.4

1984

7.0

1991

7.5

1946

7.7

1998

7.7

1996

6.9

2000

5.9

1993

7.5

2002

7.0

1999

7.7

1930

7.2

1955

7.3

1975

7.4

1987

6.2