1961

7.2

2000

6.4

1995

6.9

2004

7.9

2012

6.2

1994

6.2

2002

5.8

2013

6.3

2005

6.7

2004

6.6

2012

6.4

2008

6.5

2005

5.9

1990

7.0

2006

5.1

2003

5.7

2007

6.0

2014

6.5

2007

6.5

2006

6.5