Year	% of total
1990	95.8905132549989
1995	96.11429522393975
2000	96.62337039464211
2005	96.22803296121566
2010	96.70167861941509
2011	97.1056597664155
2012	95.15676891487463
2013	94.55395428595376
2014	91.3652332643064
2015	90.46465729534603
2016	87.37091633438556
2017	87.3742636500065