Year	% of revenue
2012	6.624980540559909
2013	8.023265232950957
2014	8.33474987065983
2015	8.17734903743206
2016	7.988508556307954
2017	7.647293175799069
2018	7.748613672437997
2019	7.544358402144108
2020	5.875405786839321
2021	6.8450516629888325