Year	% of expense
2002	35.022103770754754
2003	42.718280905860645
2004	40.88979826712203
2005	40.04871058719769
2006	40.84311923112184
2007	39.29957691093834
2008	32.482220252182316
2009	32.000833262597
2010	31.163106607510848
2011	29.076657480768585
2012	29.03839180163481
2013	27.015099334572835
2014	25.229099871159466
2015	24.380956280641826
2016	22.967893034982083
2017	21.862081867316167
2018	21.150400181176888
2019	18.346402095865532
2020	15.743217787196246
2021	13.62338574457082