Year	% of total
1990	95.7572558405993
1995	94.9795142161478
2000	94.4369921067678
2005	94.6602987503099
2010	95.3088961823302
2011	95.6959124881391
2012	94.486901261428
2013	90.6196725434764
2014	82.2580831394793
2015	88.5180407260833
2016	77.0319700350026
2017	77.9710619178659