Year	% (national estimate)
1961	33.687405159332314
1966	41.91895113230036
1971	46.23334578508281
1976	55.23065288631207
1979	55.56136302793111
1980	57.14249243691043
1981	57.33266707667076
1982	57.65391122418671
1983	58.21753526083896
1984	59.4059405940594
1985	61.08955066265379
1986	63.661648783317084
1987	64.95314698309043
1988	66.27457235136967
1989	67.8988945736023
1990	69.11354225920388
1991	69.64646938256057
1992	70.08012085570154
1993	70.31080052207962
1994	71.46738392153667
1995	72.63551503163484
1996	73.11471399643939
1997	73.4101275185251
1998	73.78758286798889
1999	74.24838048834505
2000	75.61824713241515
2001	76.62413558001364
2002	76.98350791174504
2003	78.18903581113193
2004	77.89057147251702
2005	79.05008947025289
2006	79.65838939180024
2007	80.11417697431017
2008	80.63752151462995
2009	81.27229982021849
2010	81.02726380808932
2011	81.5924740568325
2012	81.95948865933391
2013	82.23685132012046
2014	82.68596555514841
2015	83.15306825693752
2016	84.06605858025041
2017	84.67381464297839
2018	85.28686387530477
2019	85.71790113042012
2020	85.96128037463237
2021	86.67912402146062
2022	87.6078828258975
2023	87.68661942242514