Year	% (national estimate)
1961	41.19
1971	49.27
1976	58.158
1977	59.258
1978	60.402
1979	62.374
1980	63.889
1981	64.823
1982	63.818
1983	64.491
1984	65.021
1985	65.842
1986	67.082
1987	67.509
1988	68.023
1989	68.46
1990	67.344
1991	66.098
1992	64.462
1993	62.243
1994	61.862
1995	61.344
1996	60.366
1997	59.21
1998	60.115
1999	61.559
2000	62.879
2001	63.237
2002	65.264
2003	66.479
2004	66.07
2005	65.705
2006	67.221
2007	67.626
2008	67.943
2009	66.362
2010	65.896
2011	65.629
2012	65.476
2013	65.512
2014	65.808
2015	65.613
2016	65.195
2017	65.106
2018	64.519
2019	66.1
2020	61.931
2021	64.234
2022	66.047
2023	65.092