Year	% of total
1990	99.3867834108356
1995	99.4000856183658
2000	98.7874160645804
2005	99.1798577875221
2010	99.2702605079039
2011	99.3881695609009
2012	99.2574490020726
2013	99.344491180018
2014	99.0918385994689
2015	98.9332931278204
2016	96.163868233867
2017	96.1496281663295