Year	% of revenue
2005	5.333615826398693
2006	5.163769603094375
2007	5.19488735522846
2008	4.654008751761477
2009	4.11427762128818
2010	3.682285642837048
2011	2.849924585218703
2012	3.0566766626832917
2013	3.0069091075855576
2014	2.868935442864331
2015	2.6858980261512637
2016	2.842865759720919
2017	2.9003116537699745
2018	2.9814072211376996
2019	2.9574383269530062
2020	3.5577688413097364
2021	3.9153509286213173