Year	% (national estimate)
1965	48.48
1975	62.96
1976	64.46
1982	66.53
1983	65.03
1984	64.84
1985	66.41
1986	67.5
1987	66.54
1989	69.04
1990	68.859
1991	65.82
1992	60.757
1993	54.656
1994	53.374
1995	46.819
1996	42.626
1997	39.761
1998	38.272
1999	41.39
2000	40.398
2001	52.543
2002	50.564
2003	50.735
2004	48.198
2005	51.349
2006	51.871
2007	52.74
2008	53.079
2009	50.985
2010	51.288
2011	52.781
2012	53.439
2013	55.158
2014	56.048
2015	56.518
2016	55.546
2017	55.377
2018	55.461
2019	56.192
2020	51.888
2021	54.885
2022	56.618
2023	57.144