Year	% of expense
1972	6.509707458490732
1973	6.1468501313261985
1974	8.323381464191366
1975	7.4833871852709875
1976	7.76368112099981
1977	8.194070080862534
1978	7.6226901781147856
1979	9.46853878339234
1980	10.446159349925896
1981	11.648827991627451
1982	12.895409521780806
1983	12.909999275939468
1984	14.255557221792845
1985	15.817535545023699
1986	15.195269526952696
1987	15.055359087273674
1988	15.276415676873341
1989	15.360957001214942
1990	15.272365217526584
1991	15.53663296079475
1992	15.222510420840274
1993	14.363516300980987
1994	14.186331292404436
1995	14.927932579828774
1996	15.622948992607085
1997	15.298588229635152
1998	14.923261899710022
1999	13.824863649658479
2000	12.862149278422324
2001	16.043792292735503
2002	13.725318326284675
2003	12.32462519435157
2004	12.249525875666485
2005	12.731072028110363
2006	13.081461511718745
2007	13.50921943243569
2008	11.539866892474077
2009	9.574240264314316
2010	9.729467989401135
2011	10.760162749263936
2012	10.873782625823473
2013	10.778531805201924
2014	11.029109019241574
2015	10.487587518022998
2016	10.77750769780124
2017	10.978054590325224
2018	11.805573692165988
2019	11.904292984493885
2020	7.714714517427784
2021	7.88793828036146
2022	11.507500071397839