Year	% (national estimate)
1961	81.4
1966	78.56
1971	72.3
1976	71.82
1979	76.992
1980	78.084
1981	78.714
1982	78.038
1983	76.622
1984	75.775
1985	75.579
1986	75.933
1987	74.824
1988	74.656
1989	75.4
1990	75.274
1991	72.553
1992	72.213
1993	71.649
1994	72.941
1995	73.665
1996	73.784
1997	72.532
1998	72.071
1999	71.828
2000	71.863
2001	72.234
2002	71.678
2003	71.401
2004	71.174
2005	72.014
2006	72.072
2007	71.789
2008	71.967
2009	70.409
2010	69.608
2011	68.784
2012	68.232
2013	67.365
2014	66.875
2015	67.8
2016	67.198
2017	67.413
2018	68.145
2019	68.259
2020	65.959
2021	68.151
2022	70.593
2023	71.057