Year	% of total
1990	99.9999999994236
1995	99.518901817375
2000	99.9610474499346
2005	97.4054565967769
2010	96.8365990451871
2011	99.968368976096
2012	96.1308352548498
2013	94.2902797874458
2014	88.5680566665015
2015	93.2225650943946
2016	83.4325081469574
2017	84.6133660520254