Year	% (national estimate)
1960	45.258103241296524
1961	45.958986731001204
1962	46.21951219512195
1963	47.05159705159704
1964	47.77777777777778
1965	48.69888475836431
1966	50.12437810945273
1967	51.11940298507462
1968	51.9350811485643
1969	53.508771929824576
1970	54.32873274780427
1971	54.86725663716815
1972	55.64005069708491
1973	56.7258883248731
1974	58.06861499364676
1975	59.43517329910141
1976	61.03225806451612
1977	62.29086229086229
1978	64.18485237483952
1979	65.42416452442158
1980	66.53746770025839
1981	67.66233766233766
1982	68.66840731070496
1983	69.24083769633506
1984	70.15706806282722
1985	71.42857142857143
1986	72.47706422018348
1987	73.49081364829397
1988	74.2782152230971
1989	75.13089005235601
1990	75.26178010471205
1991	75.72559366754618
1992	76.2532981530343
1993	76.79045092838196
1994	78.35416583469777
1995	78.67821452365091
1996	79.09025482460818
1997	79.77252750179794
1998	79.91427312422385
1999	80.34528907922912
2000	80.12565165084882
2001	80.3124538237309
2002	80.45936681870934
2003	80.95037274854438
2004	80.68625044322614
2005	80.81366010665141
2006	80.80556463029511
2007	80.996408232386
2008	81.51960851507134
2009	82.27012452746276
2010	82.35418071476737
2011	82.44625753813409
2012	82.2189597913311
2013	82.04164754474532
2014	82.3157164735458
2015	82.08110065170166
2016	82.09541979216351
2017	82.57684344640866
2018	82.65585402939686
2019	83.04508777511063
2020	83.0589382832821
2021	82.97607952780366
2022	83.54862439311461
2023	84.16571244017734