Year	% (national estimate)
1973	88.24
1976	85.98
1985	87.9
1986	87.58
1987	87.43
1988	86.74
1989	82.44
1990	81.443
1992	80.807
1993	85.33
1995	79.025
1996	76.487
1997	76.624
1998	75.456
1999	74.63
2001	73.961
2002	74.112
2003	73.339
2004	74.488
2005	74.333
2006	74.508
2007	74.357
2008	74.978
2009	74.153
2011	73.452
2012	71.484
2013	71.488
2014	71.193
2015	69.891
2016	67.648
2017	66.53
2018	66.699
2019	67.294
2020	62.668
2021	65.102
2022	68.144
2023	68.278