Year	% (national estimate)
1960	74.53
1970	66.68
1980	71.2
1990	58.16
1992	47.521
1993	44.746
1994	42.683
1995	44.571
1996	38.986
1997	39.935
1998	44.981
1999	44.588
2000	42.842
2001	38.899
2002	36.103
2003	34.5
2004	30.825
2005	30.324
2006	30.207
2007	29.545
2008	28.714
2009	27.746
2010	27.534
2011	26.997
2012	27.902
2013	30.975
2014	33.008
2015	34.389
2016	36.138
2017	36.477
2018	37.071
2019	37.247
2020	35.294
2021	35.073
2022	34.049
2023	35.459