Year	% of total
1990	3.40962645627292
1995	2.72642583630081
2000	2.12865311547638
2005	2.98168108063589
2010	3.17597858712209
2011	4.69641322772346
2012	2.1582003707563
2013	2.01324730963205
2014	1.41902595446868
2015	1.8782071700423
2016	1.35294157404438
2017	1.36157024347089