Year	% (national estimate)
1961	83.58
1966	80.25
1971	75.93
1981	69.04
1983	69.891
1984	72.092
1985	75.281
1986	75.204
1987	75.83
1988	76.647
1989	77.442
1990	76.697
1991	74.655
1992	72.666
1993	70.406
1994	69.003
1995	67.885
1996	68.334
1997	68.31
1998	67.795
1999	66.838
2000	67.002
2001	65.65
2002	65.526
2003	64.036
2004	63.973
2005	64.118
2006	63.712
2007	63.111
2008	63.033
2009	60.113
2010	59.673
2011	59.503
2012	59.795
2013	58.658
2014	58.36
2015	59.095
2016	57.823
2017	57.186
2018	57.705
2019	55.173
2020	54.97
2021	50.66
2022	54.407
2023	54.925