Year	% of total
1990	75.0251662773227
1995	50.2316205525778
2000	37.3755047208565
2005	33.5060622763983
2010	28.9085348455114
2011	39.6700055141489
2012	20.5092327671875
2013	14.4038354832779
2014	5.73045615268372
2015	11.3310365109024
2016	8.40789598474311
2017	8.48041300495846