Year | Value | 2017 | 7.36 | 2016 | 7.09 | 2015 | 7.34 | 2014 | 6.9 | 2013 | 7.55 | 2012 | 6.8 | 2011 | 7.92 | 2010 | 7.43 | 2009 | 7.93 | 2008 | 8.29 | 2007 | 8.53 | 2006 | 8.45 | 2005 | 8.48 | 2004 | 9.41 | 2003 | 9.63 | 2002 | 9.27 | 2001 | 10.86 | 2000 | 11.56 | 1999 | 16.84 | 1998 | 12.43 | 1997 | 14.66 | 1996 | 14.35 | 1995 | 18.55 | 1994 | 27.03 | 1993 | 27.16 | 1992 | 30.99 | 1991 | 27.4 | 1990 | 21.32 | 1989 | 31.6 | 1988 | 22.79 |
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