Year	% (national estimate)
1978	39.34
1979	40.83
1980	40.49
1981	41.84
1982	41.56
1984	44.09
1985	41.45
1986	40.229
1987	41.852
1988	42.711
1989	43.698
1990	44.442
1991	47.09
1992	47.104
1993	46.382
1994	45.722
1995	45.622
1996	45.175
1997	45.732
1998	48.943
1999	49.651
2000	50.22
2001	50.803
2002	51.197
2003	50.799
2004	50.392
2005	50.519
2006	50.593
2007	50.643
2008	50.939
2009	50.033
2010	49.238
2011	47.492
2012	46.208
2013	45.276
2014	46.105
2015	46.895
2016	47.528
2017	49.011
2018	50.425
2019	50.865
2020	49.7
2021	50.106
2022	51.156
2023	51.739