Year	% of revenue
1999	37.06346702401358
2000	32.67176384266102
2001	27.83997923175016
2002	26.525495719234733
2003	22.88540723486367
2004	21.498934091148225
2005	27.957274118373316
2006	31.31736538997586
2007	29.238231084835302
2008	31.338060932309418
2009	33.87074040844953
2010	31.375376872743253
2011	35.304444960002826
2012	34.359459740849765
2013	34.14843898161553
2014	33.82188665590966
2015	40.006267295984365
2016	44.541583635266704
2017	43.99257871020043
2018	43.688157126982176
2019	40.365386278971364
2020	40.09770121456949
2021	43.352006510132505
2022	26.27389808995675