Year	% of expense
1998	15.725149472126546
1999	15.491106511141666
2000	18.871880055818572
2003	17.272762286511302
2008	12.741717319521173
2009	13.094666887542344
2010	11.00382720141859
2011	10.773670994151018
2012	9.65289638555788
2013	7.359484852407864
2014	7.537538115986263
2015	8.778003790885117
2016	10.60985978199165
2017	10.63128066218248
2018	9.895563708451695
2019	10.298283676387822
2020	9.420935748973028
2021	10.291574950204424
2022	13.300535604390666