Year	% of total
1990	99.954661962427
1995	99.9538252143842
2000	99.9619335362535
2005	99.9631116184999
2010	99.9643895445421
2011	99.9646504112679
2012	99.964937755683
2013	99.9652794693565
2014	99.9657025025398
2015	99.9662317940315
2016	99.8934934401901
2017	99.8946743201431