Year	% (national estimate)
1960	62.89
1970	61.91
1980	61.48
1990	51.53
1992	43.579
1993	40.859
1994	38.965
1995	38.413
1996	33.938
1997	34.394
1998	39.63
1999	39.785
2000	37.754
2001	34.073
2002	32.324
2003	30.583
2004	27.25
2005	27.073
2006	26.722
2007	25.729
2008	25.128
2009	24.659
2010	24.804
2011	24.288
2012	25.694
2013	27.386
2014	29.523
2015	31.018
2016	32.29
2017	32.438
2018	32.263
2019	32.19
2020	31.199
2021	31.773
2022	30.834
2023	31.408