Year	% of revenue
2008	11.017850930796277
2009	11.473228048715235
2010	10.700593965697125
2011	10.938482783189453
2012	11.894687457741737
2013	11.623040666068402
2014	11.806867350027563
2015	10.967143925596663
2016	11.277601899137903
2017	10.160027360793409
2018	10.868404726522487
2019	10.957815227493061
2020	9.673200324639305