Year	% of revenue
2007	34.23429788328634
2008	34.68931514794292
2009	35.14590267515165
2010	33.63789168663453
2011	34.05713189918101
2012	35.53753020840811
2013	31.622837572296557
2014	31.32848117774078
2015	29.859379957756317
2016	29.118953847709594
2017	29.133699083423604
2018	30.07783103946467
2019	30.26703177676202
2020	32.422532278093556
2021	32.422532278093556
2022	29.62920425354325