Year	% (national estimate)
1961	71.06
1966	69.47
1971	63.2
1975	64.5
1977	60.14
1981	60.59
1983	60.422
1984	59.046
1985	57.737
1986	56.356
1987	54.378
1988	52.231
1989	50.84
1990	49.944
1991	49.038
1992	46.039
1993	46.687
1994	46.376
1995	44.956
1996	43.469
1997	45.572
1998	48.502
1999	50.594
2000	51.431
2001	49.86
2002	48.734
2003	49.418
2004	48.88
2005	50.496
2006	52.747
2007	69.372
2008	65.964
2009	60.059
2010	53.862
2011	51.369
2012	50.273
2013	49.89
2014	48.055
2015	47.423
2016	50.462
2017	46.686
2018	46.721
2019	47.062
2020	43.681
2021	52.122
2022	52.026
2023	53.903