Year	% (national estimate)
1961	67.9
1970	62.24
1981	23.1
1983	45.977
1984	43.673
1985	43.193
1986	43.865
1987	42.809
1988	38.541
1989	38.2
1990	37.028
1991	37.584
1992	36.713
1993	36.121
1994	37.333
1995	35.998
1996	35.551
1997	34.655
1998	35.75
1999	35.536
2000	38.722
2001	37.158
2002	37.317
2003	38.055
2004	35.841
2005	37.633
2006	37.384
2007	36.116
2008	35.966
2009	34.896
2010	35.185
2011	34.129
2012	34.964
2013	33.661
2014	32.254
2015	32.799
2016	30.692
2017	30.635
2018	31.451
2019	32.46
2020	30.265
2021	32.199
2022	32.414
2023	32.853