Year % of total 1990 99.9999999989308 1995 99.9999999989595 2000 100 2005 100 2010 100 2011 100 2012 99.999999999993 2013 99.999999999993 2014 99.8181262460333 2015 99.8185107661135 2016 99.5631292580941 2017 99.5653335783953