Year	% (national estimate)
1961	85.09
1971	76.85
1980	66.36
1981	73.54
1982	66.1
1983	66.28
1984	68.72
1985	67.99
1986	68.64
1987	69.68
1988	67.62
1989	66.09
1990	66.28
1991	66.55
1992	66.86
1993	64.99
1994	65.338
1995	64.614
1996	62.895
1997	61.414
1998	61.656
1999	62.645
2000	60.737
2001	59.289
2002	60.537
2003	59.7
2004	58.229
2005	59.459
2006	59.212
2007	60.399
2008	60.716
2009	60.397
2010	60.106
2011	60.853
2012	60.648
2013	59.952
2014	58.469
2015	58.579
2016	58.407
2017	55.935
2018	57.505
2019	58.155
2020	57.814
2021	59.109
2022	59.358
2023	60.092