Year	% of revenue
1990	5.815441308186401
1991	13.596622227049334
1992	25.642376692567847
1993	26.15233680210763
1994	10.02817929986
1995	14.877663382144824
1996	9.175963659961065
1997	4.431578947368421
1998	30.305208809881705
1999	25.271090869659506
2001	5.589874898188841
2002	1.8758156445704603
2003	28.38305873871955
2004	28.179457132477353
2005	30.998823834948556
2006	22.8063299201411
2007	34.94094096064191
2008	25.437454509349816
2009	29.00016457720229
2010	22.620071597668872
2011	30.119053637602434
2012	18.66977218954506
2013	18.94006172340326
2014	15.828490753953917
2015	27.522398850843803
2016	32.63636087607097
2017	23.232375999843665
2018	18.770754583839015
2019	19.59585965227697
2020	22.79387798510936
2021	31.17780607447418