Year	% of revenue
1995	5.529269547090541
1996	5.9635512117692375
1997	5.765730824679768
1998	6.286710861816987
1999	8.497109763715978
2000	10.410821099104565
2001	10.843122727921493
2002	10.01012610610591
2003	7.055867041962339
2004	6.383520500802331
2005	4.872634250127926
2006	4.205983814072294
2007	4.191168459174837
2008	4.001612727508087
2009	4.105640504755243
2010	3.839665839819552
2011	4.260578014841592
2012	5.014427188549607
2013	5.011031409804163
2014	5.008930593478531
2015	4.26705573409316
2016	4.385572342491556
2017	3.930619125972268
2018	3.6565205360512665
2019	3.2941030151271233
2020	3.1527278314899014
2021	2.858086461073754
2022	2.6948750940755795