Year	% of expense
1972	18.562769041553192
1973	17.515386726253478
1974	16.697426989469115
1975	14.908858135706883
1976	13.947574864067953
1977	13.538348444008822
1978	13.277445464855129
1979	12.677019633086578
1980	11.53983748147391
1981	11.26879741104167
1982	11.173980189583556
1983	10.75350565973982
1984	10.880273160377902
1985	10.470192067847343
1986	10.37050133584787
1987	10.704684082214749
1988	10.670698485343793
1989	10.423870655304542
1990	10.060750316975085
1991	9.826503459286855
1992	9.715808045661909
1993	9.445650915972852
1994	9.162336587787523
1995	8.86228461052994
1996	8.69812886208562
1997	8.543976526611992
1998	8.487752552042812
1999	8.638102393228078
2000	8.662197165930214
2001	9.756472893753838
2002	10.286058235608762
2003	10.841245617715856
2004	10.939558138817167
2005	10.799519688629404
2006	10.69054412782056
2007	10.57629180382054
2008	10.109483911222034
2009	9.896661212688617
2010	10.014485781781051
2011	10.137171734809506
2012	10.239454775478327
2013	10.056448757107809
2014	9.863996719793526
2015	9.72459096365312
2016	9.685223424241808
2017	9.601017130125381
2018	9.487081613873482
2019	9.257013920563836
2020	7.000242366993343
2021	6.7458086648098075
2022	8.062109158280453