Year	% of revenue
2004	20.04765377824823
2005	21.690566049951467
2006	19.166384216179424
2007	19.578442850807726
2008	21.292193225016838
2009	18.292862388506396
2010	17.64025614850904
2011	18.32116242554146
2012	19.738795866984624
2013	20.013449725685472
2014	19.968037048267153
2015	18.480151422656192
2016	16.863742805369327
2017	16.661264903419312
2018	15.568474352218796
2019	15.943294043413042
2020	14.815662000869475
2021	16.466099563690438
2022	16.229410270237242