Year	% of total
1990	98.3726367101208
1995	98.5084855977309
2000	98.3802181745139
2005	97.8411428834689
2010	97.7079289673215
2011	97.7669904429505
2012	98.7909542668195
2013	98.6683930935144
2014	91.7830596877595
2015	99.2825492757675
2016	98.9194415810399
2017	98.9371786266806