Year	% of revenue
1995	13.783240408730077
1996	17.33945337391827
1997	17.835532946690062
1998	14.073867907368163
2002	8.90334138394167
2003	8.305587739985924
2004	7.564354796759942
2011	3.4489432778994114
2012	3.89082209684152
2013	3.5648915641057837
2014	2.9020730113831568
2015	2.910301926894837
2016	1.6580200047880946
2017	1.5869311199419855
2018	1.4692797243529698
2019	1.5009126960307941
2020	1.5662481171350662
2021	1.3611026436398668