Year	% of total
1990	32.0146823689655
1995	22.9203783784752
2000	15.2029939259422
2005	15.1800961459676
2010	17.4079104122711
2011	17.808212058015
2012	6.26667105743068
2013	4.22504484416795
2014	1.52288622376012
2015	1.45746984462927
2016	1.3814784788063
2017	1.37704624880247