Year Percent 2000 80.81867 2001 76.17761 2002 80.31175 2003 80.44974 2004 80.53443 2005 80.02448 2006 79.64742 2007 81.38389 2008 83.7362 2009 84.19249 2010 83.88874 2011 84.02323 2012 84.20538 2013 84.74413 2014 85.55655 2015 84.92645 2016 84.49104 2017 84.38168