Year	% (national estimate)
1976	58.43
1978	67.03
1979	64.23
1980	79.98
1982	66.69
1984	67.39
1987	72.87
1988	76.57
1989	77.73
1990	76.11
1994	70.36
1996	66.02
1997	66.98
2000	67.546
2007	67.843
2009	63.43
2010	63.276
2011	65.36
2012	64.88
2013	61.919
2014	61.185
2015	60.727
2016	59.751
2017	58.886
2018	59.21
2019	58.574
2020	58.544
2021	58.486
2022	59.225
2023	60.124
