1964

6.5

1971

4.6

2002

5.9

1999

6.8

1997

7.8

2000

6.5

2004

8.7

1925

6.7

1962

7.4

1963

6.6

1931

7.2

1931

7.5

1967

6.0

1925

7.5

1951

7.0

1920

4.3

1978

6.9

2008

7.0

2007

5.7

1974

7.1