Year	% of expense
1990	2.251715982597478
1991	2.2468229553356487
1992	1.7935774889915153
1993	2.1216603979717554
1994	2.4230068769056112
1995	5.984982443436639
1996	5.4012533484173195
1997	5.069592648957552
1998	5.360132804273322
1999	5.259697019125433
2000	5.693061526203701
2001	6.689415523398506
2002	5.854501290905027
2003	5.900565643936117
2004	6.845965776903718
2005	6.771208927518147
2006	6.581554811182085
2007	6.3778241676015615
2008	7.035300508336805
2009	7.515403116866001
2010	7.872569251396302
2011	7.55430413186988
2012	7.549396127691851
2013	6.584249350394279
2014	7.40855640740166
2015	6.37270213594706
2016	6.410148455996923
2017	6.593679403375129
2018	6.311395635470406
2019	6.2465659784756316
2020	6.698941447308323
2021	6.310278141484011
2022	7.806920288081634