Year	% (national estimate)
1976	83.08
1978	85.86
1979	83.44
1980	90.64
1982	80.09
1984	84.63
1987	86.25
1988	88.54
1989	89.28
1990	87.97
1994	85.18
1996	82
1997	81.9
2000	80.129
2007	81.184
2009	79.81
2010	79.472
2011	80.49
2012	80.6
2013	78.76
2014	78.229
2015	77.47
2016	76.366
2017	75.562
2018	75.926
2019	74.965
2020	74.59
2021	74.33
2022	75.326
2023	76.101