Year	% (national estimate)
1960	26.91
1970	45.11
1978	61.89
1979	63.67
1980	61.99
1981	62.46
1982	61.32
1984	57.19
1985	55.46
1986	53.006
1987	54.281
1988	53.928
1989	53.318
1990	53.042
1991	50.987
1992	45.988
1993	43.014
1994	41.56
1995	38.931
1996	38.279
1997	39.771
1998	43.348
1999	42.099
2000	39.9
2001	41.554
2002	41.757
2003	41.404
2004	38.021
2005	38.103
2006	37.644
2007	37.836
2008	38.075
2009	37.227
2010	34.216
2011	35.866
2012	34.907
2013	33.753
2014	33.848
2015	32.82
2016	31.245
2017	32.344
2018	31.697
2019	32.454
2020	28.173
2021	27.203
2022	28.98
2023	33.48