Year Percent 2001 74.44028 2002 74.41285 2003 74.46314 2004 74.51304 2005 74.56294 2006 75.45251 2007 76.33912 2008 77.22277 2009 78.10345 2010 78.98116 2011 79.85591 2012 80.69239 2013 81.51375 2014 82.33595 2015 83.16541 2016 84.00183 2017 84.84359 2018 85.69062 2019 86.54158 2020 87.39567 2021 88.25226 2022 88.28423