Year	% (national estimate)
1973	62.45
1976	59.13
1985	64.35
1986	64.12
1987	64.64
1988	64.31
1989	61.57
1990	61.324
1992	64.058
1993	67.57
1995	61.758
1996	59.521
1997	59.727
1998	59.082
1999	58.994
2001	59.895
2002	60.678
2003	60.193
2004	61.415
2005	61.695
2006	61.989
2007	61.918
2008	62.406
2009	61.789
2011	60.704
2012	59.162
2013	59.217
2014	59.224
2015	58.358
2016	56.479
2017	55.973
2018	56.308
2019	56.953
2020	52.031
2021	54.076
2022	57.499
2023	57.768