Year % (national estimate) 1960 27.398255813953487 1977 39.23855015453779 1979 42.211055276381906 1980 42.28927897867401 1981 44.61919324304645 1982 48.467238122911525 1983 49.614167140752414 1985 51.8138495904691 1986 53.21168966028779 1987 58.365008305881695 1988 59.61947142470013 1989 60.16088844593151 1990 61.969981503184 1991 63.11147430117222 1992 65.54871546980962 1993 66.410285681669 1994 67.73895753444114 1995 68.61850983734641 1996 70.00823793426696 1997 70.80932938083785 1998 71.29677088672476 1999 73.5021892146539 2000 73.9897505978818 2001 74.96530706647438 2002 75.38787404549257 2003 77.10634463361687 2004 77.89849618915997 2005 77.81462049667716 2006 78.85255806764371 2007 79.81836388417568 2008 80.45089945190728 2009 81.43494403191843 2010 82.54035206118891 2011 83.36974098555987 2012 83.66393905191875 2013 83.60056457304165 2014 82.96519220941457 2015 83.8130675904937 2016 84.41250449155586 2017 84.67599060884092 2018 84.98799442135986 2019 85.60819608797058 2020 86.40581927345677 2021 88.17666217430369 2022 87.88008683748393 2023 87.6776991804288