Year	% of total
1990	94.6288509562629
1995	94.8949865578172
2000	95.3178584404272
2005	95.7371617329771
2010	96.0181024318068
2011	96.2561659139301
2012	95.3647306390659
2013	95.3651760087435
2014	95.2323733359172
2015	94.2948066111285
2016	93.6286819246882
2017	93.7299726265532