Year	% (national estimate)
1961	21.52
1971	31.08
1978	31.16
1979	34.52
1980	36.16
1990	41.07
1991	38.4
1992	32.84
1993	34.61
1994	34.71
1995	31.95
1996	30.18
1997	29.19
1998	35.6
1999	33.84
2002	31.42
2003	33.91
2004	32.05
2006	33.18
2007	30.87
2009	34.48
2010	32.792
2011	32.373
2012	33.442
2013	33.419
2014	32.086
2015	31.27
2016	32.285
2017	32.434
2018	33.036
2019	33.3
2020	33.143
2021	32.698
2022	33.785