Year	% (national estimate)
1960	90.53
1970	85.42
1978	77.93
1979	78.28
1980	80.09
1981	79.86
1982	78.84
1984	67.02
1985	66.39
1986	69.7
1987	68.642
1988	67.187
1989	65.781
1990	63.768
1991	62.236
1992	56.199
1993	52.004
1994	48.902
1995	47.166
1996	46.166
1997	48.478
1998	50.801
1999	50.493
2000	49.6
2001	51.472
2002	52.379
2003	48.255
2004	47.148
2005	46.002
2006	45.521
2007	44.695
2008	43.61
2009	40.118
2010	37.966
2011	40.373
2012	39.186
2013	36.219
2014	34.751
2015	34.213
2016	35.025
2017	35.57
2018	36.565
2019	36.042
2020	32.431
2021	32.185
2022	33.139
2023	37.128