1985

7.1

1997

6.8

2006

7.8

1966

6.5

1975

6.3

1974

5.9

1986

6.3

1981

6.4

1983

6.5

1926

7.9

1996

6.9

1933

7.5

1976

6.6

1986

7.0

1997

5.7

2003

6.6

2000

7.1

1995

5.4

2005

6.2

2006

5.6