Year	% of total
1990	86.6681583955522
1995	84.0415370594808
2000	81.2965803144091
2005	81.3705259932321
2010	84.0671860788674
2011	82.3121360362645
2012	78.3037070713761
2013	75.6354862997347
2014	63.4273228218982
2015	66.2238981773309
2016	60.2745062519442
2017	60.049834521458