Year	%
1979	70.45274
1980	51.42857
1981	48.40909
1982	49.97345
1983	51.87897
1984	43.23178
1985	63.23927
1987	57.34503
1989	55.85714
2001	87.75612
2002	87.73354
2003	88.83123
2004	93.74447
2005	98.91858
2006	92.80867
2007	94.27636
2008	93.4601
2009	96.44122
2010	97.80495
2011	97.23412
2012	96.05454
2013	96.32944
2014	98.20288
2015	97.65182
2016	99.44483
2017	94.41203