Year	% of revenue
2005	24.99365952314319
2006	34.89456701554688
2007	38.31493032094144
2008	38.72047326875822
2009	33.779757814163375
2010	33.52199444727004
2011	39.96873290019891
2012	36.59545570955395
2013	37.30759493243005
2014	38.88536041968516
2015	35.454620696518134
2016	35.43216964167965
2017	35.64598837955646
2018	39.19232550143003
2019	36.32470376909415
2020	36.17232384764618