Year	% (national estimate)
1976	55.678
1977	55.692
1978	56.421
1979	58.886
1980	59.769
1981	60.404
1982	55.041
1983	54.596
1984	56.163
1985	57.78
1986	59.522
1987	61.018
1988	62.475
1989	63.372
1990	61.283
1991	57.331
1992	54.761
1993	53.353
1994	53.757
1995	53.789
1996	52.652
1997	51.475
1998	52.45
1999	54.542
2000	56.231
2001	56.339
2002	57.466
2003	58.155
2004	57.853
2005	57.703
2006	59.347
2007	60.489
2008	60.497
2009	56.418
2010	56.015
2011	56.469
2012	55.902
2013	56.659
2014	56.738
2015	57.119
2016	56.61
2017	57.937
2018	57.893
2019	58.701
2020	49.693
2021	55.493
2022	58.703
2023	57.976