1996

6.5

1976

7.7

1946

7.6

1968

7.2

1998

5.6

1973

6.9

1946

6.9

1955

7.8

1938

7.4

1987

7.3

1989

7.0

1992

6.7

1998

6.6

1978

7.6

1996

7.0

2000

6.1

2006

6.8

1975

7.8