Year	% of total
1990	2.09461116678142
1995	1.29725472205583
2000	1.08049102552235
2005	1.48022430330524
2010	1.4022313136594
2011	1.12709821945884
2012	1.12131896141892
2013	0.908567106613045
2014	1.04324008628338
2015	0.720148385361885
2016	0.591934315393661
2017	0.587027165475273