1992

6.8

2003

7.1

2010

6.7

2000

8.0

1988

8.3

1982

7.6

2009

7.4

2001

8.1

2005

8.2

2009

8.0

2014

7.2

2018

7.0

1999

7.4

2007

8.6

2016

7.7

1993

7.1

2004

8.0

2013

7.3

1997

6.6

2016

7.8