1974

6.6

2006

5.1

2020

5.0

1962

6.8

1982

6.4

1997

7.4

1986

7.5

1953

8.0

1940

7.9

1973

6.5

2000

6.0

1990

7.0

1991

8.3

2003

6.5

2003

7.7

1999

7.5

1951

7.7

1987

6.5

1993

5.5

2017

6.2