Year	% of revenue
2000	5.608247294928294
2001	8.867419032792908
2002	9.165450177708616
2003	10.071034712819607
2004	11.37888529418208
2005	12.046743865035207
2006	12.154480641606758
2007	11.375719755947628
2008	9.775539287885444
2009	11.276491174840803
2010	11.046800392060238
2011	11.768916219429022
2012	14.778989446153062
2013	15.271645214154658
2014	15.258577858210764
2015	14.668783715815739
2016	14.396474411517952
2017	13.635389506018502