Year	% of revenue
1995	17.514846228872674
1996	17.460448011091596
1997	17.18514172955388
1998	16.787468090995766
1999	16.288189694482444
2000	15.497466336620832
2001	15.930999930896276
2002	17.325180713526958
2003	17.569904211127174
2004	17.435207941016884
2005	17.121930560912343
2006	16.09467285452892
2007	14.955051738641314
2008	13.562180189590608
2009	14.668099606061476
2010	15.272187420278351
2011	14.462108657604672
2012	14.052288630158522
2013	13.924665030204475
2014	13.961157501737196
2015	13.770325203252032
2016	13.898558274007867
2017	13.949174118231495
2018	13.475665693117818
2019	13.70374038493282
2020	13.331037020959355
2021	13.422085382296542
2022	14.073860098722154