Year	% (national estimate)
1973	22.24840914447325
1994	22.772678185745143
1999	31.187410586552218
2004	14.035087719298245
2005	13.953488372093023
2006	13.838120104438643
2007	13.756613756613758
2008	13.65461847389558
2009	13.479028098276094
2010	14.856206228579943
2014	9.22975782778865