Year	% of total
1990	94.9569304676805
1995	95.1730368096553
2000	95.456690230932
2005	97.879940719733
2010	96.9973111624753
2011	97.4765309879375
2012	98.1690101298309
2013	94.0245854882111
2014	92.0061005865964
2015	93.5081780350891
2016	90.4198926637437
2017	90.537343806725