Year	% of total
1990	99.9498372788963
1995	99.9434882389513
2000	99.9275858751292
2005	99.9206310182723
2010	99.9130291744281
2011	99.9114364079122
2012	99.9098193754425
2013	99.9081686560107
2014	99.9064749441913
2015	99.9047290269472
2016	99.902928320825
2017	99.9010957436499