Year	% (national estimate)
1980	39.886
1981	38.359
1982	38.784
1983	38.562
1984	35.403
1985	35.186
1986	36.368
1987	37.342
1988	36.883
1989	37.509
1990	38.511
1991	40
1992	39.555
1993	39.143
1994	39.293
1995	39.622
1996	38.626
1997	37.172
1998	31.542
1999	31.665
2000	32.236
2001	33.909
2002	34.883
2003	34.36
2004	34.586
2005	33.6
2006	30.974
2007	28.494
2008	26.636
2009	24.996
2010	25.7
2011	25.806
2012	26.553
2013	26.301
2014	27.673
2015	28.696
2016	28.772
2017	28.532
2018	28.432
2019	27.749
2020	26.469
2021	29.082
2022	30.67
2023	29.735