Year % of total 1990 100 1995 99.9842109816904 2000 99.957431968077 2005 100 2010 99.9566358235583 2011 100 2012 99.955997318409 2013 97.6859593235148 2014 16.5989802462163 2015 90.8480627384849 2016 17.4195577199093 2017 17.8244594869492