Year	% of expense
1986	1.2292028805562454
1987	5.099729509819014
1988	7.689317643732994
1989	4.8794444702206965
1990	25.688502673796794
1991	27.576058477992987
1992	29.236968018131453
1993	30.92388560567814
1994	27.50197858957804
1995	27.860471087549183
1996	30.508201670524304
1997	32.665171265407025
1998	31.9868771785934
1999	31.40074211502783
2000	32.75055905671885
2001	32.33535158426507
2002	34.642131165079704
2003	33.12888245014942
2004	32.64845133046975
2005	33.75447708200511
2006	34.57100724027769
2007	33.405670553187115
2008	33.53717650868333
2009	30.04460758574324
2010	31.423312829149662
2011	33.116883116883116
2012	33.76815330170837
2013	32.99040685069654
2014	34.0256717196802
2015	35.034863017172576
2016	35.332754987266334
2017	32.42430077798263
2018	33.97417297041635
2019	33.504522216462505
2020	41.67280357024357
2021	38.31078661655688
2022	35.264169097638224