1996

5.8

2013

6.7

2006

6.6

2011

5.6

1984

7.2

2008

5.6

1980

8.4

2010

6.4

2009

6.3

1980

6.7

2008

6.3

2009

7.3

1999

7.6

1967

5.3

2009

7.3

1972

8.7

1999

6.8

2002

6.0

2012

7.7

1977

7.7