Year	% of total
1990	95.74961522218547
1995	95.96893744972517
2000	96.46724285625098
2005	96.1142761080706
2010	96.56881112884166
2011	96.94794188023494
2012	95.04447322098062
2013	94.44180170491327
2014	91.1716856174583
2015	90.24623151177663
2016	87.05648383791033
2017	87.06600740577079