Year	% of total
1990	87.7864770930427
1995	88.9516621437366
2000	89.4665141622671
2005	94.2397151112789
2010	95.213002688386
2011	92.5762579606023
2012	94.3008166078541
2013	86.6746380835255
2014	68.5990109973735
2015	61.2812082032929
2016	49.6699685649635
2017	46.8178084404756