Year	% (national estimate)
1966	67.14
1977	63.08
1992	64.69
1995	59.69
1996	56.22
1997	50.096
1998	49.932
1999	47.797
2000	45.69
2001	43.131
2002	41.682
2003	38.799
2004	40.431
2005	35.905
2006	35.123
2007	35.897
2008	35.892
2009	35.887
2010	36.53
2011	35.319
2012	35.335
2013	35.125
2014	34.827
2015	36.992
2016	33.898
2017	34.627
2018	34.582
2019	35.659
2020	35.535
2021	32.908
2022	31.581
2023	29.852