Year	% of revenue
1995	21.768018928806026
1996	19.464399517371874
1997	19.155074627350846
1998	19.360753739708777
1999	19.672668911949224
2000	16.135913780123943
2001	16.985050449838415
2002	16.48513437251146
2003	16.706610553106596
2004	15.472093535932366
2005	16.856878020797172
2006	17.910677039321765
2007	18.64044926985212
2008	19.73245035887773
2009	15.895451219510544
2010	15.970436797107702
2011	15.35656899594694
2012	15.748077724984
2013	16.15563002299733
2014	17.0733677407225
2015	17.025910471382794
2016	18.411676200620665
2017	19.43659760279033
2018	19.462761968363353
2019	19.016847071400136
2020	18.81393005283885
2021	20.16402666680806
2022	19.988218744986057