Year	% of total
1990	21.2743977787724
1995	21.6170407090679
2000	43.1002528516089
2005	37.9501018409187
2010	28.9473306850212
2011	43.4059149330924
2012	28.3140407514933
2013	19.6229059474482
2014	16.2360579880222
2015	15.9377748527351
2016	0.91525310055498
2017	0.909455553671057