Year	% of expense
1974	17.048054919908427
1975	16.16883605447295
1976	16.65269023723862
1977	15.706290807337556
1978	10.22936719229981
1979	10.117725455353176
1980	11.195578545762675
1981	12.837003825320696
1982	12.28646911451564
1983	11.831724642687812
1984	11.762622208000408
1985	11.111173926562456
1986	10.00353613890867
1987	10.812122219366449
1988	10.548014822309813
1989	11.287175346521314
1990	11.389669859120636
1991	9.698892628132281
1992	11.181191788392402
1993	12.569216708779098
1994	11.064000894235665
1995	7.278587050296252
1996	7.108231328838399
1997	7.462087178909962
1998	7.242575630331148
1999	7.632490725707998
2000	8.207666800398297
2001	8.23364543580645
2002	8.95563243717166
2003	8.7310761182594
2004	8.790630832463737
2005	9.433905305394653
2006	9.731787899078782
2007	8.916890063284498
2008	9.510479725442794
2009	9.590833415009318
2010	9.419048335026838
2011	8.649069326374835
2012	8.160407409137486
2013	8.243445763280471
2014	7.918841223427226
2015	8.480405177818746
2016	8.269281333365827
2017	8.109958575142379
2018	8.229396662852071
2019	8.064154472294058
2020	7.618182746443301
2021	8.116468960918517
2022	8.163269587551596