Year	% of total
1990	92.4616179585345
1995	92.8283726327335
2000	92.5475663600368
2005	92.8957025313891
2010	92.5745810154467
2011	93.6081415728039
2012	90.9609575664715
2013	90.2175353423032
2014	85.6669960230579
2015	85.3633037647214
2016	82.7404668498229
2017	82.3139391670813