Year	%
1979	89.07729
1980	89.30212
1981	90.45054
1982	91.49042
1983	91.35985
1984	91.09534
1990	98.43076
1991	98.72892
1992	98.86352
1993	99.18158
1994	99.28307
1995	99.24045
2001	99.03403
2002	99.86439
2003	99.78889
2004	99.8867
2005	99.94512
2006	99.83983
2007	99.97307
2008	99.85646
2010	99.79166
2011	99.95428
2012	99.96111
2013	99.74758
2014	99.79976
2015	99.63259
2016	99.56228
2017	99.93234