Year	% of expense
2010	19.727724415146916
2012	22.57551254439448
2013	17.974652762877454
2014	19.908051386355723
2015	18.282253001567135
2016	19.93859935762656
2017	21.862081867316167
2018	19.989316036844535
2019	18.346402095865532
2020	15.927077615873673
2021	16.792294830875846