Year	% of total
1990	99.999936972279
1995	99.9981918214152
2000	99.9744971158326
2005	99.8425892769862
2010	99.7842091250178
2011	99.9883118328215
2012	99.415705395871
2013	98.8124199615413
2014	97.5483691973325
2015	98.332247641107
2016	97.8534475485002
2017	97.898540316706