Year	% of revenue
2013	24.33075286295286
2014	25.616598604450687
2015	25.766196257727696
2016	23.64643138997929
2017	25.771400763018516
2018	23.109408317489446
2019	23.725156318457742
2020	23.79861922436238
2021	22.29585366766244
2022	21.06687983222966