Year Percent 1991 53.317 1992 54.24 1993 57.53 1994 59.359 1995 58.401 1996 62.465 1997 58.06 1998 60.564 1999 60.01 2000 62.134 2001 64.029 2002 63.056 2003 63.681 2004 63.186 2005 64.329 2006 65.872 2007 65.869 2008 65.588 2009 67.84 2010 70.728 2011 71.284 2012 70.627 2013 71.727 2014 72.226 2015 72.931 2016 73.384 2017 74.7 2018 75.217 2019 75.659 2020 76.089 2021 76.504 2022 76.919