Year	% of total
1990	13.6237530332909
1995	12.9583905804287
2000	11.2277948646954
2005	10.8443913574875
2010	10.4691787348714
2011	12.6992038538699
2012	7.45268764547811
2013	1.45695713821642
2014	0
2015	0
2016	0
2017	0