Year	% (national estimate)
1960	55.7
1970	50.44
1980	60.71
1981	59.5
1982	60.04
1983	60.91
1984	58.79
1985	60.31
1986	64.35
1987	65.94
1988	67.11
1989	62.27
1990	60.508
1991	57.659
1992	56.743
1993	55.476
1994	55.433
1995	54.839
1996	60.842
1997	63.704
1998	65.802
1999	64.734
2000	65.992
2001	66.118
2002	65.534
2003	63.657
2004	62.959
2005	60.312
2006	57.429
2007	58.846
2008	61.909
2009	57.988
2010	56.968
2011	55.516
2012	57.062
2013	57.21
2014	54.434
2015	55.804
2016	54.6
2017	53.783
2018	54.263
2019	55.442
2020	55.417
2021	61.278
2022	64.229
2023	65.772