Year	% of total
1990	99.8504158631154
1995	99.8444731910239
2000	99.7822997655559
2005	99.7555551735633
2010	99.7327254682949
2011	99.7282821441406
2012	99.8315844255985
2013	99.6894465465339
2014	99.4244611918943
2015	99.4136246272235
2016	99.1474357970737
2017	99.1509298844018