Year	% of total
1990	35.9164378701246
1995	40.6036921880443
2000	48.9034848479221
2005	63.3310337623032
2010	69.2407819918567
2011	58.7788715982295
2012	52.0165823956359
2013	47.7160411376569
2014	39.2452243621816
2015	30.1423312599886
2016	23.2610590764949
2017	24.5123007157922