Year	% of total
1990	50.7562805788856
1995	18.1675175383815
2000	18.0227763693333
2005	17.5859898364987
2010	18.4109502120119
2011	19.3405266321983
2012	6.9085833559777
2013	5.67217832573003
2014	4.38159298079516
2015	4.80185570092386
2016	4.40677865229389
2017	4.4174470537565