Year	% of revenue
1994	17.504336007204444
1995	30.78112428362006
1996	19.50519438791903
1997	19.979092692808713
1998	20.536559695376173
1999	21.460890155885558
2008	17.679044288573103
2009	13.192603074724882
2010	10.189049223188697
2011	12.077166238293598
2012	13.592310312338268
2013	13.812641169939896
2014	13.98373293125783
2015	17.29333412170697
2016	14.828628841159407
2017	13.481492890611065
2018	11.072372676900278
2019	9.651049225013656
2020	13.16461975557326
2021	11.70143681133959