Year	% (national estimate)
1977	25.45
1979	26.41
1980	27.52
1981	28.74
1982	28.76
1983	29.34
1985	30.484
1986	29.77
1987	35.667
1988	36.514
1989	37.264
1990	39.109
1991	40.356
1992	42.512
1993	42.96
1994	43.855
1995	44.12
1996	45.291
1997	47.023
1998	48.477
1999	50.474
2000	52.268
2001	53.716
2002	54.266
2003	54.332
2004	54.06
2005	51.773
2006	52.662
2007	54.405
2008	55.664
2009	55.891
2010	55.45
2011	55.593
2012	55.608
2013	54.905
2014	53.917
2015	54.513
2016	54.912
2017	55.698
2018	56.771
2019	57.822
2020	57.501
2021	59.984
2022	61.13
2023	61.682