1963

7.1

1984

6.9

1991

8.3

1994

8.7

1985

7.0

1953

8.0

1955

7.5

1940

7.9

1983

7.2

1930

7.3

1986

7.9

1972

8.7

1974

8.6

2002

6.7

2005

6.7

2004

8.0

1999

8.4

1972

7.1

2001

7.4

1990

7.8