Year	% (national estimate)
1976	41.947
1977	42.266
1978	43.363
1979	45.087
1980	46.387
1981	47.724
1982	46.529
1983	46.845
1984	47.692
1985	49.123
1986	50.284
1987	51.262
1988	52.717
1989	53.595
1990	53.766
1991	52.769
1992	51.942
1993	51.506
1994	51.884
1995	52.241
1996	52.128
1997	52.636
1998	53.716
1999	54.616
2000	55.422
2001	55.657
2002	56.567
2003	57.46
2004	57.738
2005	57.672
2006	58.045
2007	58.751
2008	58.854
2009	57.958
2010	57.802
2011	57.696
2012	57.896
2013	58.141
2014	57.687
2015	57.591
2016	57.517
2017	57.892
2018	58.028
2019	58.453
2020	54.111
2021	56.57
2022	58.316
2023	58.388