Year	% (national estimate)
1960	76.76
1973	55.43
1975	53.8
1976	60.28
1977	53.02
1978	52.87
1979	52.33
1980	51.13
1983	57.45
1984	53.54
1986	57.12
1989	43.57
1990	40.57
1991	38.71
1992	42.68
1993	44.31
1994	45
1995	46.51
1998	42.4
1999	46.59
2001	38.33
2002	39
2005	50.35
2006	46.21
2007	46.46
2008	49.329
2009	48.26
2010	49.461
2011	47.95
2012	47.976
2013	48.123
2014	46.184
2015	42.916
2016	41.933
2017	38.22
2018	36.146
2019	35.656
2020	37.247
2021	38.383
2022	34.997