Year	% of expense
1990	2.1418296730056974
1991	2.1712016962188456
1992	2.1714119978730606
1993	2.228653341627674
1994	2.3299511461856444
1995	2.2697120158887785
1996	2.245790105593695
1997	2.8917044605597773
1998	3.0485087691377277
1999	12.134816710971087
2000	10.72202370111723
2001	9.932229932229934
2002	9.838145824242515
2003	10.37755042725106
2004	10.430903568716781
2005	10.197807959677283
2006	10.297001060718074
2007	10.48513713500154
2008	10.47484281113636
2009	9.83882513980369
2010	10.286547676124473
2011	10.52072119465151
2012	10.532223747251122
2013	11.480292675324936
2014	10.580859013161184
2015	10.43099184485674
2016	10.642126368824224
2017	10.64210658982208
2018	10.345291489101886
2019	10.526542943461372
2020	9.957034872472297
2021	8.827677598117138
2022	9.49417851519171