Year	% (national estimate)
1980	39.917
1981	38.264
1982	38.17
1983	36.189
1984	33.177
1985	31.988
1986	32.258
1987	32.738
1988	31.518
1989	31.978
1990	32.519
1991	34.557
1992	34.551
1993	33.59
1994	34.497
1995	34.605
1996	33.728
1997	32.19
1998	27.114
1999	27.64
2000	27.942
2001	29.028
2002	30.108
2003	29.493
2004	29.804
2005	28.334
2006	26.096
2007	24.194
2008	22.006
2009	20.935
2010	21.22
2011	21.792
2012	22.612
2013	22.747
2014	24.309
2015	25.345
2016	25.394
2017	25.273
2018	24.527
2019	24.849
2020	23.563
2021	25.319
2022	26.962
2023	25.762