Year	% of total
1990	99.83715553239189
1995	99.80603214773355
2000	99.77591880359773
2005	99.77572952335413
2010	99.79941562083458
2011	99.82164886730561
2012	99.72140921078999
2013	99.67695558623747
2014	99.33440513162353
2015	99.43307343913223
2016	98.9777034958042
2017	98.98955000637687