Year	% of expense
1998	43.37221796803011
1999	42.228089428706674
2000	45.00729596770379
2003	20.181066454813944
2008	18.3588265884608
2009	18.770991479721815
2010	18.36149254698255
2011	23.026643541949046
2012	11.250473383917681
2013	7.829033418433537
2014	9.610905049244213
2015	11.140376972923043
2016	10.706787476273224
2017	11.382581820037178
2018	13.358400807543184
2019	10.6095546734081
2020	10.672134645904507
2021	9.539574876582968
2022	9.380337806613317