Year	Percent
1975	84.30476
1976	83.31424
1977	87.23242
1978	87.74962
1979	86.89602
1983	84.98671
2010	85.08713
2011	86.67774
2012	86.57407
2013	85.11551
2014	81.25
2015	79.80066