Year	% of revenue
1990	30.710486045325364
1991	28.72729548552196
1992	26.7728719145873
1993	26.694021577481546
1994	26.65589660743134
1995	28.75353408150919
1996	26.828379910585774
1997	23.324711341030905
1998	22.682304214551532
1999	21.13327093383253
2000	19.710302700414285
2001	18.214014235367287
2002	16.023697869437175
2003	14.802484927522947
2004	13.488238485844692
2005	12.276621972154791
2006	11.693549836615992
2007	10.78758272608418
2008	10.460936619934664
2009	9.95737125111424
2010	10.02012528699793
2011	9.58782641617211
2012	8.769526425040024
2013	8.436848841594994
2014	7.424005087919724
2015	6.684858285046939
2016	6.213119678967227
2017	5.725803113098195
2018	5.935678358081378
2019	6.089503247074803
2020	5.504543867430427
2021	5.219376699678606
2022	6.140760070811384