Year	% of revenue
2012	22.753619541682767
2013	22.379979051677136
2014	23.493966517176695
2015	24.540793525902185
2016	22.18301987247433
2017	22.75036496350365
2018	24.273071498982127
2019	23.650320277643896
2020	24.357188749210913
2021	25.665296115058812