Year	% of revenue
1995	19.37455913472843
2002	21.497708637123083
2003	22.08449658761112
2004	20.559254038683207
2005	21.319679654494962
2006	22.94449418633362
2007	25.66801674334093
2008	26.66252574722386
2009	29.121005594205187
2010	31.59464094191278
2011	30.891122701360313
2012	29.6371739124304
2013	31.880187013089202
2014	30.478204045480652
2015	31.21446002423615
2016	31.23088839626686
2017	32.481214892230895
2018	32.100937389286706
2019	31.691583530210167
2020	31.462712568583147
2021	29.174213359461305
2022	26.706931068307078