Year	% of expense
1990	12.168550230097361
1991	8.870893190600329
1992	11.239169594170532
1993	10.759975058072209
1994	12.261327789554144
1995	19.711925899368133
1996	14.891381218560088
1997	15.189910121877592
1998	18.026792699867475
1999	14.831563946999509
2000	13.888023836032925
2001	14.99021438324891
2002	20.609081546904342
2014	7.50889221508699
2015	9.33260832012606
2016	10.436578648796896
2017	12.67975391705625
2018	12.747159985097733
2019	13.26509390708693
2020	12.52735678788456
2021	12.377753627367376
2022	11.87392785544459