Year	% (national estimate)
1960	71.75
1970	56.12
1974	56.65
1975	57.46
1976	56.66
1978	56.63
1980	29.44
1981	59.28
1982	62.78
1985	32.77
1988	38.73
1990	54.35
1991	45.09
1994	49.77
1995	54.6
1996	52.4
1997	50.5
1998	46.79
1999	44.6
2001	41.7
2002	44.4
2003	40.21
2004	39.44
2008	38.349
2009	34.317
2010	31.001
2011	33.187
2012	30.923
2013	32.438
2014	32.768
2015	34.045
2016	36.322
2017	36.478
2018	34.315
2019	35.675
2020	34.442
2021	34.57
2022	36.076