Year	% (national estimate)
1960	51.51
1970	56.94
1980	51.27
1990	44.58
1992	39.685
1993	37.011
1994	35.28
1995	31.947
1996	28.953
1997	28.752
1998	34.17
1999	34.857
2000	32.544
2001	29.145
2002	28.472
2003	26.609
2004	23.635
2005	23.765
2006	23.171
2007	21.824
2008	21.442
2009	21.471
2010	21.97
2011	21.462
2012	23.381
2013	23.624
2014	25.874
2015	27.485
2016	28.251
2017	28.199
2018	27.211
2019	26.857
2020	26.88
2021	28.295
2022	27.461
2023	27.17