Year	% of total
1990	99.45194115531453
1995	99.47402975481926
2000	99.49981396371518
2005	99.56424276150192
2010	99.49637744215788
2011	99.60776534253934
2012	99.49245463507337
2013	99.1797771809939
2014	98.84594653908479
2015	98.85283026897683
2016	98.35068260265037
2017	98.26011016465034