Year	% (national estimate)
1961	46.18
1970	47.66
1981	21.24
1983	41.76
1984	40.787
1985	41.445
1986	41.558
1987	40.188
1988	36.804
1989	33.789
1990	34.072
1991	35.38
1992	35.714
1993	32.694
1994	32.981
1995	31.681
1996	29.888
1997	29.322
1998	29.414
1999	30.116
2000	32.645
2001	29.956
2002	30.24
2003	28.814
2004	32.155
2005	32.328
2006	31.935
2007	31.56
2008	30.776
2009	29.929
2010	29.766
2011	29.783
2012	27.906
2013	28.245
2014	28.078
2015	27.117
2016	26.153
2017	25.449
2018	27.746
2019	29.45
2020	26.527
2021	28.24
2022	29.66
2023	30.246