1979

8.7

2005

5.2

1999

7.6

1996

6.6

2008

7.6

2007

6.4

1937

7.0

2003

6.6

1957

7.9

1974

5.3

1962

4.6

1970

5.6

1998

7.2

2000

6.5

1960

7.7

1958

6.6

1960

6.7

1965

7.2

2004

6.1

2007

7.5