Year	% of total
1990	14.226137861707
1995	14.8848821282628
2000	19.0444165176786
2005	19.4218968666218
2010	19.7528046534757
2011	19.8133809268111
2012	0
2013	0
2014	0
2015	0
2016	0
2017	0