Year % (national estimate) 1960 54.97845065753122 1970 45.23484942372041 1974 71.96904557179708 1975 76.09468907150742 1976 75.66699604743083 1978 80.29735132433782 1980 59.86968754627573 1981 81.76573865061451 1982 81.62288239626811 1985 61.902580546648345 1988 68.56767794632438 1990 81.13379274476661 1991 56.91659401336822 1994 84.27664460353911 1995 80.46875 1996 80.26490066225166 1997 79.08847184986595 1998 78.26382285015623 1999 77.3972602739726 2001 73.42465753424658 2002 76.27586206896552 2003 74.25049033342674 2004 75.03392130257801 2007 77.55102040816327 2008 74.73171125802847 2009 74.53822740476159 2010 74.69026295459098 2011 74.80221462395743 2012 75.98058336583887 2013 76.37639516583161 2014 76.25283593233968 2015 80.06092179804708 2016 79.4447357605476 2017 80.24780209700407 2018 80.07941477854949 2019 80.55800540366496 2020 79.91081092782613 2021 80.1341360522816 2022 82.09985935302392