Year	% of total
1990	98.70858982800776
1995	98.29724751144693
2000	98.48885190224556
2005	98.50295459096813
2010	98.6908144395211
2011	98.55504910703746
2012	98.32536989822876
2013	97.6934933654878
2014	97.43581741794651
2015	97.05207020436899
2016	96.70954345491127
2017	96.69512280182622