Year	% of total
1990	99.8523149942362
1995	99.8528751783441
2000	99.8727407380566
2005	99.8818307736368
2010	99.8902288688839
2011	99.8918670223278
2012	99.8934970269965
2013	99.8951027732676
2014	99.8966798819469
2015	99.898232709866
2016	99.8997716893208
2017	99.9013050997327