Year	% of total
1990	36.3730725969582
1995	35.553769069102
2000	35.9089595176273
2005	17.4328392469783
2010	32.723712049818
2011	22.1901583787351
2012	22.2599262364502
2013	32.8735683545971
2014	26.6433090342503
2015	35.1356008557006
2016	24.0830166181376
2017	29.7036625700031