Year	% of revenue
2008	61.21581917553263
2009	61.597941794569245
2010	63.558678727957215
2011	60.21657924532647
2012	58.97680452993392
2013	54.96376347888855
2014	55.89381244839717
2015	50.76446063330459
2016	52.59550496677142
2017	50.29063985764062
2018	52.29134673055454
2019	56.637608157987906
2020	63.346039747332824