Year	% (national estimate)
1960	43.42
1973	31.67
1975	31.32
1976	35.28
1977	30.93
1978	31.78
1979	30.8
1980	30.44
1983	37.78
1984	36.43
1986	35.76
1989	35.7
1990	33.24
1991	30.43
1992	31.84
1993	32.65
1994	33.28
1995	33.54
1998	30.32
1999	34.03
2001	28.21
2002	29.9
2005	36.27
2006	33.76
2007	33.64
2008	35.487
2009	35.347
2010	34.735
2011	33.475
2012	33.569
2013	34.463
2014	33.787
2015	32.033
2016	31.356
2017	28.956
2018	24.458
2019	22.8
2020	22.772
2021	24.111
2022	22.587