Year	% of expense
1995	40.268972176036726
1996	38.12038659585249
1997	43.778180532827314
1998	42.07765557699801
1999	40.62978036584547
2000	34.79680190269248
2001	40.967265761271506
2002	40.26450501587795
2003	42.24150722288168
2004	46.59745181360541
2005	46.35924588209982
2006	46.63703853597683
2007	48.33509438610046
2008	49.894748309956306
2009	48.58796211171182
2010	50.98549088957481
2011	49.36394420606979
2012	50.08840957491554
2013	50.131549011408374
2014	49.642167866734766
2015	47.59857648790043
2016	48.78794317972117
2017	47.25674522320804
2018	45.74359846442208
2019	45.29528624005096
2020	44.374529201308135
2021	44.822612850375116
2022	46.445290373895034