Year	% of expense
1985	3.2124138743301334
1986	2.009330035971223
1987	2.070773263433814
1988	1.208700089297104
1989	0.3219051786104947
1991	0.12139940403928925
1992	0.6396190905700632
1993	2.6358884813843506
1994	4.382794662628071
1995	5.727605727605728
1996	6.64250024492995
1997	14.79333420810917
1998	12.489723966675989
1999	14.72770248475779
2000	11.467317641391062
2001	10.234214054898255
2002	7.692784130910082
2003	5.16813808153953
2004	4.652336458398876
2005	3.9075392826610313
2006	2.400959048517063
2007	1.9747737835313264
2008	2.0250695928011915
2009	5.079806930522545
2010	4.931239630961849
2011	5.656534683724668
2012	6.51727435785877
2013	6.39893259668399
2014	5.341112009714129
2015	4.660177913583617
2016	4.273063120379516
2017	3.8693078711764306
2018	3.2936500434344733
2019	3.3599726789297124
2020	3.6297974616904183
2021	3.86454715196351
2022	3.9381417989713015