Year % of total 1990 99.99999999998808 1995 99.99999999999005 2000 100 2005 100 2010 100 2011 100 2012 100 2013 99.99999999999868 2014 99.99998986967148 2015 99.99996295670361 2016 99.98917854485124 2017 99.97115933229274