Year	% (national estimate)
1960	66.15
1970	60.03
1980	65.74
1981	64.93
1982	66.79
1983	65.67
1984	64.21
1985	64.12
1986	66.99
1987	68.69
1988	70
1989	65.69
1990	63.907
1991	59.596
1992	59.247
1993	58.099
1994	57.762
1995	54.257
1996	61.231
1997	65.981
1998	67.062
1999	66.537
2000	68.186
2001	67.508
2002	65.059
2003	64.133
2004	61.507
2005	60.524
2006	56.931
2007	57.594
2008	61.607
2009	57.201
2010	57.001
2011	54.448
2012	56.359
2013	56.088
2014	53.174
2015	55.078
2016	53.989
2017	53.591
2018	54.05
2019	55.221
2020	55.292
2021	59.485
2022	63.815
2023	65.185