Year Percent 2000 59.96821 2001 61.69976 2002 63.45162 2003 65.22379 2004 67.01626 2005 68.82904 2006 70.66213 2007 72.51553 2008 74.38924 2009 76.28325 2010 78.19757 2011 80.1322 2012 82.08713 2013 84.06238 2014 86.05793 2015 86.05793 2016 86.05793 2017 86.05793 2018 86.05793