Year	% of expense
1972	14.285714285714285
1973	8
1974	11.428571428571429
1975	7.6923076923076925
1976	8.333333333333332
1977	15.887850467289718
1978	13.836477987421384
1979	10.119047619047619
1980	10.945273631840797
1981	16.937119675456387
1982	18.872660885440435
1983	29.94279847462599
1984	27.11310799426553
1985	25.137288737755668
1986	25.14050078966909
1987	26.627791563275434
1988	20.265001426443085
1989	19.957395787917275
1990	18.252310401026044
1991	18.224690198640346
1992	15.32280264796487
1993	15.595797851550932
1994	14.653714948830043
1995	13.828581677659201
1996	12.820547879649697
1997	12.081042218231413
1998	12.719604112852384
1999	11.818916650792097
2000	13.07922631049351
2001	13.041567499325874
2002	18.082800010058143
2003	12.062664847281571
2004	13.294228130973426
2005	14.033992372544454
2006	12.691285436719541
2007	12.692863566755111
2008	13.973500520054523
2009	12.819418894282563
2010	10.78196808745233
2011	10.858378158087739
2012	9.598255454534305
2013	9.417822741828315
2014	6.827791246551692
2015	5.945402719833211
2016	6.0529346602904255
2017	6.0304706686248055
2018	6.586754801173504
2019	5.870501831568131
2020	4.6886483473548735
2021	7.251873784680968
2022	9.568160690306172