Year	% of total
1990	7.40270575030497
1995	6.27860204094423
2000	4.70514985813889
2005	4.14879847569512
2010	4.29464534965659
2011	4.74203558575162
2012	2.65137167035512
2013	2.33065935013265
2014	1.98038107579176
2015	1.90708396087286
2016	0
2017	0