Year	% (national estimate)
1961	63.07
1966	62.28
1971	55.59
1975	50.88
1977	52.75
1981	53.32
1983	55.185
1984	54.575
1985	53
1986	52.011
1987	50.368
1988	47.69
1989	46.954
1990	45.665
1991	44.601
1992	42.321
1993	43.831
1994	43.346
1995	41.448
1996	40.121
1997	41.866
1998	44.595
1999	46.772
2000	46.738
2001	44.808
2002	44.558
2003	45.54
2004	44.733
2005	47.561
2006	48.167
2007	64.184
2008	61.853
2009	57.395
2010	51.686
2011	49.131
2012	48.594
2013	48.104
2014	45.823
2015	44.596
2016	48.291
2017	45.486
2018	45.016
2019	45.897
2020	43.095
2021	51.7
2022	53.215
2023	54.218