Year	% of total
1990	73.9647315809138
1995	74.3777086649108
2000	75.1542614896248
2005	89.8907436678508
2010	90.7875639449817
2011	89.1000474572607
2012	85.8572303075218
2013	90.3324956146356
2014	76.7688039228704
2015	62.6371372098775
2016	42.63526838332
2017	42.8866914585793