Year	% of total
1990	99.7826789991177
1995	99.8030684479091
2000	99.8402892184996
2005	99.8681611745573
2010	99.7975904125968
2011	99.8329593936825
2012	99.7382261784997
2013	99.7063987809564
2014	98.7735958810507
2015	98.4025281460127
2016	96.7566797602139
2017	96.5881931419251