Year	% (national estimate)
1960	27.6
1970	23.61
1980	25.31
1981	23.64
1982	25.73
1983	25.29
1984	26.82
1985	26.26
1986	25.75
1988	25.72
1989	24.9
1990	25.11
1991	24.1
1992	26.58
1993	28.3
1994	29.13
1995	27.46
1996	31.865
1997	32.707
1998	31.032
1999	29.9
2000	29.22
2001	27.386
2002	26.562
2003	27.671
2004	28.754
2005	29.378
2006	29.032
2007	29.866
2008	31.853
2009	31.803
2010	30.516
2011	32.257
2012	31.465
2013	30.988
2014	31.123
2015	30.096
2016	29.767
2017	30.775
2018	30.99
2019	29.72
2020	22.421
2021	23.004
2022	25.94
2023	26.624