Year Percent 1995 85.60361 1996 85.34478 1997 86.09693 1998 86.72773 1999 86.595 2000 86.60373 2001 86.94042 2002 86.64792 2003 87.21447 2004 86.97109 2005 86.41919 2006 86.54367 2007 86.83195 2008 87.32329 2009 86.9772 2010 86.66212 2011 87.10571 2012 86.98703 2013 86.80642 2014 87.32153 2015 87.58349 2016 87.84494 2017 87.79172