Year	% of total
1990	6.53738928832768
1995	6.11174409274844
2000	5.17086183462202
2005	20.6325057999453
2010	16.3141616640854
2011	27.1255004419331
2012	15.3953956344205
2013	40.9129829676163
2014	28.2305152258356
2015	25.5616562433547
2016	10.4590911783147
2017	11.5509481630566