1932

6.1

1938

7.0

2005

7.5

1958

6.4

1996

6.2

1995

7.0

1963

7.7

2006

6.9

2004

7.8

2002

7.4

2001

6.7

1976

7.8

1979

7.3

2006

6.7

2001

6.0

2002

6.8

1964

6.5

2000

7.0

1997

6.6

2007

7.4