Year	% (national estimate)
1960	76.72
1965	72.01
1970	63.92
1975	62.71
1980	65.21
1985	64.05
1988	57.09
1989	56.25
1990	54.67
1991	55.348
1992	52.978
1993	48.079
1994	51.139
1995	48.599
1996	48.53
1997	47.019
1998	46.002
1999	46.636
2000	42.521
2001	42.109
2002	40.858
2003	38.399
2004	37.787
2005	37.731
2006	37.409
2007	37.676
2008	38.138
2009	38.69
2010	38.33
2011	39.258
2012	38.206
2013	39.644
2014	40.848
2015	42.017
2016	42.431
2017	43.331
2018	43.98
2019	44.424
2020	39.052
2021	41.686
2022	43.818
2023	45.517