1950

6.8

1960

0.0

1986

6.6

1970

6.4

1996

6.1

2006

6.5

1934

6.5

2005

7.5

1924

8.1

1939

7.6

1999

6.7

1955

6.0

1997

6.9

1954

8.5

1952

7.7

1995

7.3

1926

7.9

1980

6.2

1948

7.3

2002

5.5