Year	% of total
1990	97.8386319910147
1995	94.8609373856433
2000	91.5685538214119
2005	92.8023092379323
2010	85.3420099256428
2011	93.6579754695366
2012	82.2118711593216
2013	80.6430515290907
2014	78.4210254216786
2015	78.9851157785327
2016	73.9379248075784
2017	73.9020043925455