Year	% (national estimate)
1978	55.83
1979	56.93
1980	56.36
1981	57.15
1982	56.47
1984	58.44
1985	54.26
1986	53.51
1987	54.258
1988	54.942
1989	55.893
1990	56.131
1991	58.163
1992	57.052
1993	55.685
1994	54.527
1995	54.03
1996	53.511
1997	53.947
1998	57.778
1999	57.884
2000	58.488
2001	59.076
2002	59.224
2003	58.184
2004	57.632
2005	57.171
2006	57.316
2007	57.25
2008	57.344
2009	55.568
2010	54.631
2011	52.82
2012	50.802
2013	49.685
2014	50.637
2015	51.289
2016	51.977
2017	53.714
2018	54.973
2019	55.419
2020	53.949
2021	54.004
2022	55.093
2023	55.578