Year	% (national estimate)
1960	27.559615612765455
1970	32.6835286859963
1977	37.127128408654464
1978	37.82496782496783
1979	38.488417238255465
1980	35.820895522388064
1983	34.656545545047294
1985	35.208437970868914
1987	35.442082756885924
1989	36.904913037958615
1990	36.99796644636502
1991	52.7437400106553
1992	52.45901639344264
1993	56.315007429420504
1994	54.357459379615946
1995	54.25308479915988
1996	58.32241153342071
1997	58.55263157894737
1998	59.63302752293578
1999	61.498028909329825
2000	60.14453231524407
2001	59.504132231404974
2002	63.24549237170597
2003	66.80763983628923
2004	66.96302606010595
2005	65.79080343607883
2006	66.74303982949247
2007	65.28704939919892
2008	65.43955672680586
2009	66.47678839622769
2010	65.04751847940867
2011	64.81036127420026
2012	65.59737512880308
2013	65.39541859830923
2014	65.8514367736771
2017	67.69363094147009
2018	69.74382807328855
2019	70.44111468981936
2020	70.51326473734161
2021	70.95268883703932
2022	72.59105417950184
2023	73.60951497445411