Year	%
1978	93.13013
1979	84.10313
1980	79.77923
1981	65.66011
1982	63.4879
1983	53.60691
1984	55.74258
1985	70.498
1986	69.27368
1987	77.93963
1988	67.10808
1989	79.83937
1990	74.01379
1991	69.16551
1994	85.31683
1995	72.72826
1999	80.5527
2000	83.70094
2002	79.72738
2003	81.31241
2004	82.52324
2005	82.48677
2007	81.8225
2009	87.96533
2010	93.78479
2012	85.98521
2013	82.24812
2014	87.55734
2016	86.25079
2017	84.17799