Year	% of total
1990	96.4286654928097
1995	95.1002489908761
2000	92.7305802837176
2005	93.5750613398087
2010	93.0007045460388
2011	94.7852350840776
2012	91.8209143581515
2013	86.9104974533489
2014	78.499186393826
2015	72.3111073443463
2016	49.3394536369063
2017	49.3001362303515