Year	% of total
1990	1.60112860751849
1995	1.78484528661774
2000	6.51157714318091
2005	22.2662598055946
2010	35.3417699042509
2011	24.2441880753161
2012	28.0227388066262
2013	26.4099163421764
2014	15.6837102829533
2015	4.31787545832802
2016	4.08003294393036
2017	4.09804108869612