Year	% of expense
1990	16.22386911836678
1991	4.591104734576758
1992	4.443076069139571
1993	5.238056286819389
1994	7.065316058616336
1995	5.775177203748632
1996	3.5139283498252833
1997	2.636136989896326
1998	11.875280736992872
1999	2.9516743957316476
2000	4.133785372482896
2001	9.20159670384429
2002	10.515254055326274
2003	11.932513308864861
2004	14.576187426627172
2005	10.106249011557656
2006	9.995400446140295
2007	9.813863459424043
2008	7.3600550075305655
2009	5.375136068488114
2010	6.507623876706015
2011	11.270094548959799
2012	11.196761950668462
2013	8.200585142978394
2014	9.57105111950085
2015	9.90602582959183
2016	8.306643196373132
2017	8.062502429724432
2018	9.266853270026497
2019	7.392636243004068
2020	8.817618952277641
2021	9.338465645767359
2022	10.630387750945038