Year	% (national estimate)
1960	73.37
1970	70.72
1980	66.95
1990	69.15
1991	68.624
1992	68.56
1993	69.343
1994	65.094
1995	63.842
1996	66.428
1997	66.958
1998	67.217
1999	68.598
2000	68.283
2001	67.766
2002	69.263
2003	69.353
2004	67.057
2005	65.656
2006	68.618
2007	67.374
2008	67.132
2009	67.268
2010	68.111
2011	68.559
2012	67.584
2013	68.011
2014	67.904
2015	67.519
2016	68.355
2017	68.669
2018	67.99
2019	66.478
2020	65.016
2021	65.383
2022	65.018
2023	66.424