Year Percent 2000 83.63807 2001 83.64988 2002 83.66169 2003 83.67349 2004 83.646 2005 83.6185 2006 83.59099 2007 83.56346 2008 83.53593 2009 83.50838 2010 83.48083 2011 83.45326 2012 83.42568 2013 83.39809 2014 83.37049 2015 83.34287 2016 83.31525 2017 83.28761 2018 83.25997 2019 83.23231 2020 83.23231 2021 83.23231 2022 83.23231