Year	% of revenue
2001	24.11550055529113
2002	27.673151750972764
2003	19.201303993480032
2004	3.891457557088444
2005	6.633754581857349
2006	10.905147578409522
2007	6.914380273548463
2008	6.842777798107995
2009	3.5233126786724904
2010	1.5480695183906836
2011	0.37061257068890596
2012	0.4363374180709545
2013	0.5733162926496826
2014	0.5296930217738101
2015	1.8744097603307894
2016	2.579356275581495
2017	8.198149082566442
2018	8.798145618371493
2019	12.138226358931362
2020	8.508850201338587
2021	9.049468537180056