Year	% (national estimate)
1960	81.61
1970	73.96
1973	81.45
1976	78.42
1980	76.37
1985	82.3
1986	82.4
1987	83.08
1988	82.11
1989	83.407
1990	82.223
1991	81.17
1992	82.556
1993	80.78
1995	79.216
1996	75.426
1997	76.603
1998	75.784
1999	75.629
2001	73.713
2002	74.416
2003	73.742
2004	74.394
2005	75.553
2006	74.165
2007	73.283
2008	72.789
2009	72.203
2011	67.854
2012	65.468
2013	64.253
2014	63.039
2015	62.677
2016	62.087
2017	62.512
2018	62.679
2019	63.175
2020	58.164
2021	60.85
2022	62.53
2023	60.416