Year	% of total
1990	2.33189166015004
1995	0.143007624461577
2000	0.417869515683589
2005	0.459593146793702
2010	0.498857878857273
2011	0.577279593523439
2012	0.48888586759932
2013	0.493276750166971
2014	0.530250863610426
2015	0.588591371340741
2016	0.559057327409584
2017	0.563497840415816