Year	% of expense
1983	21.755215914604562
1984	22.539828607580375
1985	23.373278671291917
1986	23.21827663272908
1987	20.251577859389087
1988	15.535884660235343
1989	13.605221237569404
1990	17.878342245989305
1991	9.485696225407382
1992	15.422227818349702
1993	11.703738900602858
1994	11.037614029241471
1995	6.846302779231877
1996	7.345863711497376
1997	7.026326608037588
1998	7.447956395464161
1999	3.200624512099922
2000	4.1869877110664255
2001	5.121530521374137
2002	4.862059379777525
2003	5.865648813187699
2004	5.937869019113408
2005	6.133448611299695
2006	5.817871938144639
2007	5.0393050500107055
2008	3.419397634932581
2009	4.0986709730442215
2010	4.614796355629392
2011	4.029365762025127
2012	4.500768684813351
2013	7.136126407192266
2014	6.690870761843415
2015	5.274543250185371
2016	7.207306289749509
2017	5.643903077832189
2018	6.016256550948665
2019	5.385111147429372
2020	6.0262544813294445
2021	4.314245427952102
2022	2.084575892246291