Year	% (national estimate)
1961	38.02149987202457
1971	52.24505825369812
1976	58.8325415524056
1977	59.998968513886375
1978	61.51911404262963
1979	63.02039461929193
1980	64.59774810427145
1981	66.31185783851312
1982	67.6599997404182
1983	68.91352146026047
1984	70.1127844057631
1985	71.58925033885936
1986	72.50299276531514
1987	73.46840516343953
1988	74.93540051679585
1989	75.69923009783359
1990	76.85203431469148
1991	77.86335834121769
1992	78.30943580161664
1993	78.65073519382383
1994	78.68751539029796
1995	79.32433551378652
1996	79.6267043565015
1997	80.01052223514426
1998	80.9447879981143
1999	81.38728483408394
2000	82.10405551101651
2001	82.68733134989276
2002	83.42030652915314
2003	84.30272155174762
2004	84.71831178416205
2005	84.69156490803951
2006	85.15501369184406
2007	85.74925061188571
2008	85.66921789701807
2009	86.37262904497723
2010	86.81332442811822
2011	86.54997632773555
2012	86.88506276793319
2013	87.17783685462432
2014	86.83536465223632
2015	86.55026753027317
2016	86.92246678564346
2017	87.07217340860534
2018	87.3977319616966
2019	87.50443180690085
2020	86.7455724293982
2021	87.41927631484742
2022	88.45705570024606
2023	88.43940589796942