Year	% of total
1990	99.77875683286626
1995	99.78317243367945
2000	99.73970197865893
2005	99.9014367419405
2010	99.68887115018858
2011	99.82786628628261
2012	99.94219063343448
2013	99.48952851993903
2014	99.45715968043382
2015	99.59471502968778
2016	99.39220605540613
2017	99.36155257336893