Year	Percent
1975	81.69479
1976	82.37675
1977	84.30939
1978	81.12509
1979	81.64557
1983	80.83404
2010	83.59974
2011	82.17666
2012	84.95161
2013	79.03727
2014	77.55355
2015	78.02061