Year	% of total
1990	85.4804260926661
1995	85.2624768172508
2000	86.130043943558
2005	86.5477796648142
2010	87.0084886716954
2011	86.2759161269662
2012	87.0374960306588
2013	83.6651220828194
2014	82.2722415269797
2015	81.9530902924397
2016	78.4221968051977
2017	78.5573277504976