Year	% of revenue
1999	16.059583221166125
2000	14.291137879471435
2001	9.511764279787696
2002	6.47816726225619
2003	5.994148128687647
2004	4.033771035581223
2005	3.10502377018353
2006	2.187167940090067
2007	1.3508194203093347
2008	1.1007057257933222
2009	1.739566041627786
2010	1.6012551252294727
2011	1.520252351840996
2012	1.7646161052138538
2013	1.9449112072443857
2014	2.014311122660326
2015	2.647352380019808
2016	2.5752526491346917
2017	2.506265015472851
2018	2.3635329692858886
2019	2.6182235735764996
2020	2.361256484804616