Year	% (national estimate)
1961	55.08
1971	39.89
1981	31.7
1982	31.71
1983	42.713
1984	41.513
1985	40.559
1986	38.922
1987	38.216
1988	39.171
1989	39.833
1990	39.451
1991	38.452
1992	39.119
1993	38.267
1994	37.659
1995	37.158
1996	37.716
1997	36.403
1998	41.6
1999	39.776
2000	38.731
2001	36.205
2002	35.917
2003	34.079
2004	36.212
2005	33.42
2006	31.848
2007	30.763
2008	29.815
2009	30.487
2010	29.935
2011	29.13
2012	29.307
2013	28.514
2014	27.931
2015	25.788
2016	24.523
2017	24.894
2018	23.147
2019	22.242
2020	20.914
2021	20.721
2022	23.425
2023	24.947