Year Percent 1991 79.102 1992 79.048 1993 79.019 1994 79.012 1995 78.987 1996 78.993 1997 78.999 1998 79.019 1999 79.037 2000 79.061 2001 79.484 2002 79.813 2003 80.195 2004 81.147 2005 82.133 2006 82.596 2007 82.972 2008 83.262 2009 83.516 2010 83.622 2011 84.825 2012 86.012 2013 84.879 2014 83.625 2015 81.949 2016 81.845 2017 82.037 2018 82.236 2019 82.438 2020 82.595 2021 82.753 2022 82.915