Year	% of total
1990	92.5287490730728
1995	92.506270996378
2000	91.74729437866
2005	92.0900833394338
2010	92.5888312183221
2011	92.5604874682311
2012	89.1315240076031
2013	89.8021320331261
2014	87.8196294240481
2015	88.6686504162249
2016	75.41211147449
2017	76.7615082281987