Year	% (national estimate)
1980	66.39
1981	66.53
1982	66.16
1983	65.77
1984	66.14
1985	67.05
1986	68.99
1987	69.8
1988	68.84
1989	66.35
1990	65.815
1991	64.778
1992	64.357
1993	64.044
1994	64.85
1995	65.04
1996	67.488
1997	69.318
1998	71.104
1999	71.132
2000	71.244
2001	71.092
2002	71.13
2003	69.733
2004	69.471
2005	69.03
2006	69.414
2007	70.831
2008	71.904
2009	70.425
2010	69.316
2011	69.034
2012	69.186
2013	68.68
2014	68.418
2015	67.945
2016	67.217
2017	66.822
2018	67.4
2019	64.642
2020	60.982
2021	63.091
2022	63.603
2023	63.331
