Year Percent 2001 88.84645 2002 88.80341 2003 88.76078 2004 88.71857 2005 88.67685 2006 88.55952 2007 88.44165 2008 88.32308 2009 88.15836 2010 87.89319 2011 87.63267 2012 87.37708 2013 87.12642 2014 86.88042 2015 86.63897 2016 86.40191 2017 86.16913 2018 85.94039 2019 85.71566 2020 85.49472 2021 85.27744 2022 85.06374