Year	% of total
1990	99.8007939364211
1995	99.7913084092624
2000	99.8396047331239
2005	99.6847717855223
2010	99.8182922055447
2011	99.8386429699699
2012	99.6599207463912
2013	99.7016128639799
2014	99.6058149598559
2015	99.5492912250785
2016	99.6406697768609
2017	99.6142371657863