Year	% of expense
1972	11.84575184100091
1973	11.848245080137962
1974	10.937499999999996
1975	10.757745427398289
1976	10.105633802816904
1977	9.925586396174642
1978	10.22936719229981
1979	10.117725455353176
1980	11.014395714763973
1981	10.419518204215688
1982	10.504604479563092
1983	10.90375498532625
1984	10.13467856560337
1985	10.562926971074974
1986	10.237222464910474
1987	10.54565894154275
1988	10.21633469932338
1989	10.295542459187189
1990	10.842653461965359
1991	10.514304985666936
1992	11.181191788392402
1993	9.432089052482691
1994	10.146595034654732
1995	6.405429244366455
1996	6.921527330776701
1997	7.217231964094858
1998	7.137733399646513
1999	7.261869679948687
2000	7.3945760185267275
2001	7.938513993519876
2002	7.992641582948154
2003	7.985243242211919
2004	8.050367791050254
2005	8.015316241358624
2006	8.197604066862386
2007	8.260715674888619
2008	8.24088390512433
2009	8.417984136385606
2010	8.242303812252302
2011	7.795090307987
2012	7.66478755860568
2013	7.755790719073298
2014	7.555738976870634
2015	7.93251325507684
2016	8.074393849268723
2017	8.071486282126804
2018	8.07489213205867
2019	8.064154472294058
2020	7.926067201054791
2021	8.291769815982212
2022	8.944442073932413