Year	% of expense
2012	29.28184238433134
2014	27.889941075737788
2015	23.660376952191065
2016	20.7565354964746
2017	25.47473816049044
2018	16.79731817146267
2019	20.328173019830064
2020	19.60266258515145
2021	26.685940248401312