Year	% of revenue
2005	39.76837240925954
2006	39.987667014154304
2007	42.03197614697237
2008	37.41674701475933
2009	39.10963538798055
2010	41.120158794661
2011	43.542232277526395
2012	41.38576356790151
2013	43.02231949669286
2014	45.267606611880794
2015	41.464767518703155
2016	44.087471863998715
2017	43.34714218421508
2018	43.14046087376943
2019	40.820122009833696
2020	38.25516371807489
2021	40.13976245573331