Year	% of total
1990	29.9880450270824
1995	23.9280506834929
2000	19.8700239228514
2005	16.6777957808277
2010	17.6047697961913
2011	26.5086807943173
2012	15.2488342035633
2013	11.4436957787559
2014	7.3437431295089
2015	10.6191685349655
2016	5.56794408801204
2017	5.70233779713766