Year	% (national estimate)
1980	53.97
1981	54.87
1982	54.76
1983	55.44
1984	56.26
1985	57.65
1986	60.71
1987	62.12
1988	61.58
1989	59.48
1990	59.389
1991	59.223
1992	59.07
1993	59.035
1994	59.744
1995	60.452
1996	62.577
1997	64.349
1998	66.393
1999	66.999
2000	66.947
2001	66.985
2002	67.59
2003	66.375
2004	66.376
2005	65.645
2006	65.976
2007	67.705
2008	68.963
2009	67.902
2010	66.638
2011	66.581
2012	66.635
2013	66.152
2014	65.977
2015	65.438
2016	65.011
2017	64.569
2018	64.766
2019	62.332
2020	59.416
2021	58.214
2022	60.254
2023	59.987