Year	% (national estimate)
1965	10.006715916722632
1970	11.416151910318005
1975	18.03298569003153
1980	23.574676460300804
1983	30.493387589013228
1985	37.36475114210146
1988	42.86963036963037
1995	52.02056432329029
1996	47.300058377116166
1997	48.101999420457844
2003	57.43375858684986
2005	54.302987197724036
2006	62.150055991041434
2007	64.32616081540203
2009	64.00869465736186
2010	68.16827143512151
2015	65.21739130434783
2016	56.789982925441095