Year	Percent
1975	82.97514
1976	82.8368
1977	85.74376
1978	84.37618
1979	84.22151
1983	82.85838
2010	84.32592
2011	84.36893
2012	85.73952
2013	81.984
2014	79.34347
2015	78.88299