Year	% of expense
1990	7.8826662721017975
1991	14.371818912402892
1992	11.802311285960167
2014	4.441861023538916
2015	4.404728837598968
2016	4.510664698596954
2017	5.024751309556102
2018	5.930472874875472
2019	5.710649086263995
2020	6.748198453672637