1984

6.6

1971

6.1

1966

6.3

1991

7.0

1995

6.7

1967

6.5

2009

7.4

2011

6.6

2004

6.2

1983

5.5

2002

6.3

1988

6.2

1996

7.3

2011

7.5

2000

7.7

1983

6.7

2006

6.7

2012

6.6

2012

4.5

2008

6.2