2011

5.7

2009

6.6

2007

7.8

2001

7.9

1995

8.0

1972

8.7

1989

6.3

1991

6.8

2006

6.5

2000

6.2

1984

7.1

2002

5.6

1989

7.0

1979

8.1

1939

7.6

2010

6.4

2011

7.2

2004

6.7

1940

7.1

2012

6.3