1948

5.3

1999

6.8

2013

5.6

1998

6.9

2007

5.0

1957

5.0

2004

5.6

2006

6.4

2003

6.6

2005

6.2

1971

6.6

1987

6.2

2008

6.7

2004

6.5

2002

7.8

1965

6.3

2006

7.0

1936

6.5

1978

6.0

2002

6.1