Year % of total 1990 99.9810706530859 1995 99.9892858536742 2000 99.9858101216086 2005 99.9990192438351 2010 99.9997174919515 2011 99.9970926667125 2012 99.9987848993188 2013 99.9745398507742 2014 99.6352008949127 2015 99.3891695178291 2016 98.6523483664329 2017 98.3156239365569