1999

7.3

2001

6.8

1985

8.3

2013

8.1

2009

7.6

2008

8.5

1994

8.7

1994

8.5

2006

7.5

2010

8.4

2004

8.1

2006

8.2

2012

7.4

1997

7.9

2015

7.9

2013

6.5

2016

7.6

1972

8.7

2001

7.4

2015

7.4