Year	% (national estimate)
1977	19.663341645885286
1987	13.911772521923996
1997	11.322463768115941
2007	16.896732966333783
2012	16.66060029118602
2014	18.74139355549435
2016	20.183104452767374
2017	15.437724385528858
2021	15.777673573459158