Year	% of total
1990	94.4528252737404
1995	94.0011733162488
2000	96.9841524181991
2005	91.7850767703876
2010	96.3606613840503
2011	96.7617152248839
2012	91.6799936425317
2013	91.2361078639325
2014	90.1454807181234
2015	90.4907812948218
2016	89.1143941304432
2017	89.123573610715