| Year | Value | | 2014 | 86.779698927032 | | 2013 | 85.38962705407 | | 2012 | 86.501427676547 | | 2011 | 85.895537153403 | | 2010 | 85.622432973737 | | 2009 | 85.635611143826 | | 2008 | 86.31206617624 | | 2007 | 86.198362375588 | | 2006 | 86.764386075107 | | 2005 | 86.180041330975 | | 2004 | 86.839241005338 | | 2003 | 86.598628400509 | | 2002 | 85.776951398908 | | 2001 | 85.838539544547 | | 2000 | 86.166710520779 | | 1999 | 85.498977054338 | | 1998 | 87.135709803274 | | 1997 | 86.915114724321 | | 1996 | 86.910798205567 | | 1995 | 86.589238207633 | | 1994 | 87.123753783293 | | 1993 | 89.773486343347 | | 1992 | 90.535966549118 | | 1991 | 92.160986523231 | | 1990 | 92.658777126038 |
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