Year % of total 1990 99.66934458409764 1995 99.66391035459354 2000 99.59312986039149 2005 99.84548180490647 2010 99.50418551781053 2011 99.71575334333592 2012 99.9080613484724 2013 99.15643544904772 2014 99.1223891944588 2015 99.37478153458235 2016 99.1266532380205 2017 99.08046037387265