Year	% of total
1990	82.73810227991544
1995	81.30388879064198
2000	82.15205630339771
2005	83.39287842746302
2010	84.55834815932498
2011	84.64821770839497
2012	84.1670099958244
2013	84.17646333191989
2014	81.09675181509957
2015	81.12038980303406
2016	81.13920273213643
2017	81.14083889934268