Year	% of total
1990	98.9269555598307
1995	98.94633929997089
2000	98.97193179017792
2005	99.07733048322879
2010	98.90181894206646
2011	99.1400691788813
2012	98.88193406640588
2013	98.19507319589167
2014	97.47403809521785
2015	97.45975093333409
2016	96.66930248069386
2017	96.64907744861266