Year	% (national estimate)
1961	40.75467522407878
1966	47.65334572490707
1971	50.578649031648546
1975	56.99890736918781
1976	55.13598834385623
1979	55.048046923748906
1980	56.52980460054415
1981	58.92121212121212
1982	57.656995960337866
1983	59.45879458794588
1984	60.61898379432192
1985	60.31607765057242
1986	60.72582649763858
1987	60.57584444721426
1988	60.25993501624593
1989	59.31242916509256
1990	59.0091231626964
1991	60.636813395915254
1992	59.266854652653166
1993	59.503391782925895
1994	60.76308326888373
1995	62.1099360229795
1996	62.903013554415054
1997	63.34698190463611
1998	64.27436440677965
1999	66.4864864864865
2000	67.05368119109413
2001	69.45853324194654
2002	71.64529030478555
2003	71.69444444444444
2004	72.30747767857142
2005	73.05852560495217
2006	74.19309372797744
2007	75.3193301163781
2008	76.24444125663463
2009	76.6705069124424
2010	75.77031425610487
2011	77.40388832042099
2012	77.92202121930985
2013	78.73957716151968
2014	79.250573911022
2015	79.52897761118135
2016	79.87551564800374
2017	80.69046225863077
2018	80.50120201063598
2019	81.51530400805164
2020	81.92167920744305
2021	82.41091390245015
2022	81.76507858014867
2023	82.15543813298106