Year	% of revenue
1990	17.717525490375383
1991	16.92881791188508
1992	14.273967638983736
1993	18.290310287422027
1994	28.161570219701925
1995	29.664729957523782
1996	29.45218589331772
1997	27.019041971056986
1998	34.09141148815927
1999	32.02052113281486
2000	34.18814805709765
2001	32.79774394626195
2002	33.555627118830294
2003	35.591301197850235
2004	38.76711803047564
2005	42.20627364566765
2006	45.03866677970326
2007	43.90753680228494
2008	45.15916002158226
2009	42.733879774946764
2010	44.625508671292465
2011	45.89648921102832
2012	45.34305658990997
2013	45.50799501294162
2014	43.208515127156936
2015	44.03168264014337
2016	46.222035768798754
2017	44.81623015951704
2018	40.94202382842415
2019	41.383577538752526
2020	43.63883128006935
2021	42.30394543179485
2022	37.155361282044055