Year	% of total
1990	59.3824649896696
1995	56.9405639975174
2000	54.4143857868112
2005	32.6450538134225
2010	19.2461108262732
2011	12.8686635806609
2012	35.4566066966484
2013	4.06811143851148
2014	5.40432877096582
2015	58.6017425616739
2016	51.1526515769833
2017	51.8533865462003