Year	% (national estimate)
1960	72.83
1965	70.08
1970	64.13
1974	61.89
1976	61.31
1977	61.58
1978	61.54
1979	60.97
1981	68.92
1983	65.268
1984	74.07
1985	75.591
1986	75.219
1987	75.56
1988	75.97
1989	75.345
1990	73.478
1991	73.161
1992	72.012
1993	70.528
1994	69.1
1995	73.211
1996	73.762
1997	74.238
1998	71.557
1999	73.339
2000	71.892
2001	67.214
2002	68.819
2003	65.865
2004	66.432
2005	68.135
2006	69.938
2007	70.611
2008	69.079
2009	67.857
2010	63.973
2011	63.358
2012	60.99
2013	58.123
2014	58.269
2015	58.454
2016	59.537
2017	60.381
2018	60.068
2019	61.128
2020	60.22
2021	60.41
2022	62.779
2023	64.465