Year	% of revenue
2008	4.113486329635366
2009	3.135798201420312
2010	3.60305493286515
2011	3.3492039270309952
2012	3.473749379762406
2013	3.2859003358456707
2014	2.9020730113831568
2015	3.187895874160553
2016	3.1140548206767473
2017	3.0576945175355803
2018	3.0416642788468717
2019	2.829756559459054
2020	3.055233719102441
2021	3.4890433769734734
2022	2.7659848939672615