1960

5.2

1981

6.4

1933

6.6

1959

5.4

2009

6.9

2006

5.7

1971

4.5

1980

5.5

2008

7.7

1979

7.3

2006

5.8

1925

4.9

2003

7.2

2008

6.7

1995

6.1

1996

6.9

1997

6.4

2005

6.7

1927

5.2

1951

6.8