Year	% of total
1990	99.9635937913297
1995	99.9686091936776
2000	99.962464538289
2005	99.9762126288735
2010	99.9790019848446
2011	99.9752981852139
2012	99.932857659025
2013	99.9021862717551
2014	99.7019406270077
2015	99.3424159801006
2016	97.0506560391518
2017	95.8402199027414