Year Percent 2000 80.28567 2001 80.68665 2002 81.0852 2003 81.49766 2004 81.91303 2005 82.32221 2006 82.46542 2007 82.59924 2008 82.7237 2009 82.83876 2010 82.94455 2011 83.04115 2012 83.12863 2013 83.20702 2014 83.2764 2015 83.3371 2016 83.38944 2017 83.43375 2018 83.47036 2019 83.4996 2020 83.52181 2021 83.53727 2022 83.54633