Year	% of revenue
2000	29.519972780996184
2001	26.17555155560031
2002	27.39834243789629
2003	34.28151364179974
2004	29.27215635253105
2005	29.10158264033806
2006	73.15296304403307
2007	34.536347290007704
2008	30.965215865775665
2009	31.361259019738704
2010	27.268800230386486
2011	24.092707314422345
2012	7.874829634392613
2013	27.674274563040896
2014	13.03926320891905
2015	14.334808147250278
2016	14.217723555436384
2017	17.24963503649635
2018	15.838260114257203
2019	17.119551772570254
2020	12.931722584363342