Year	% of total
1990	10.121041740358
1995	9.49179173750969
2000	11.444812037801
2005	10.8616190674547
2010	9.71108234926238
2011	15.3276422982825
2012	9.49555057185968
2013	9.39007046996353
2014	3.34829237021917
2015	3.29045113458567
2016	0
2017	0