1994

6.6

1992

6.7

2005

6.1

2006

6.4

2010

7.8

2006

5.8

1997

6.4

2013

5.2

1999

7.6

2014

5.6

2005

6.6

2010

7.5

2009

5.7

1984

7.3

2008

7.3

2010

5.2

2013

5.6

1980

6.7

2010

7.1

1979

7.3