Year	% of total
1990	86.3624288759632
1995	84.3923231376726
2000	69.6344212955224
2005	62.419516495921
2010	69.5113186230673
2011	63.2858267517533
2012	64.452067912871
2013	66.844951717478
2014	67.4870074157167
2015	71.9664863921298
2016	69.180608891335
2017	69.7723329576781