Year	% of revenue
1996	11.505638524839988
1997	9.726006660611565
1998	12.192246097530928
1999	13.439254266087419
2000	14.536610425262076
2001	12.055247972659288
2002	11.577699547381277
2003	11.387785072563926
2004	10.985130485522848
2005	10.915966623707703
2006	10.113960654722938
2007	9.229570397664496
2008	8.008352826624687
2009	8.964680639961344
2010	9.784405414670266
2011	9.55453863951375
2012	9.396919369733348
2013	9.736909840268229
2014	10.238267162741197
2015	11.083716663091254
2016	12.46566959010644
2017	12.64186044108892
2018	13.11701163298363
2019	12.454945727330566
2020	15.325873202934359
2021	16.286033218978258
2022	14.020107638443