Year	Percent
1970	81.92728
1971	89.55921
1972	93.94234
1973	94.96854
1974	92.82277
1975	92.44915
1976	93.41911
1977	89.81922
1983	97.12237
2011	94.26261
2012	96.46618
2013	95.55192
2014	95.33039
2015	93.7303
2016	92.7776