Year	% (national estimate)
1960	28.653624856156494
1970	40.18270257444536
1980	59.8636972130948
1983	62.9553163250258
1986	66.3777686064108
1988	65.49473964575841
1990	71.02781425331266
2000	79.8941798941799
2001	79.78142076502732
2002	77.62039660056658
2004	74.68175388967467
2005	81.62962962962963
2006	78.97727272727272
2007	72.18934911242604
2009	76.4957264957265
2010	85.32526475037821
2011	81.52958152958153