Year % of total 1990 99.99999999968162 1995 99.99999999972205 2000 99.99999999956638 2005 99.99999999962883 2010 99.99999999966504 2011 99.99999999966977 2012 99.99999999966928 2013 99.99999999964935 2014 99.97624111745961 2015 99.9754677039702 2016 99.60587764504588 2017 99.3300796302866