Year	% of total
1990	99.9247928339601
1995	99.9243466739477
2000	99.7334403267887
2005	99.5054603363245
2010	99.8139746599063
2011	99.6480476639273
2012	98.6337295149329
2013	96.1758754187442
2014	95.1307982367134
2015	95.2565534422994
2016	90.0912432266097
2017	90.207468547919