Year	% (national estimate)
1960	74.89
1971	69.46
1982	67.806
1990	49.6
1994	69.181
1995	54.74
1998	53.28
1999	66.6
2000	64.7
2001	63.59
2002	61.98
2003	61.98
2004	62.28
2005	61.13
2006	56.3
2007	61.71
2008	56.52
2009	57.87
2010	53.29
2011	51.25
2012	49.3
2013	46.98
2014	46.25
2015	42.84
2016	41.22