Year	% of expense
1974	12.702188392007596
1975	11.982191250483924
1976	11.76570027892824
1977	11.437660960460546
1978	11.328365351746768
1979	11.193150089967121
1980	10.82442143382562
1981	10.280227521786783
1982	9.803640533180447
1983	9.414064275648903
1984	9.11128691983126
1985	8.99336378522793
1986	8.843140523420551
1987	8.758359519780862
1988	8.961845607808355
1989	9.129679355552017
1990	9.151717847370012
1991	8.485411235313013
1992	8.540430581454515
1993	8.537544227493106
1994	9.135212613473502
1995	6.531752102467954
1996	7.230022100042829
1997	7.184352023922765
1998	7.389925437760263
1999	7.4573337458543705
2000	7.426979721861287
2001	7.3827669324827925
2002	7.552029375683817
2003	7.46397625443321
2004	7.46542885770411
2005	7.393493823222911
2006	6.852165168109886
2007	6.83311339553528
2008	6.77008282219672
2009	6.667833333112734
2010	6.602878233480669
2011	6.530325734668099
2012	6.5619553323581075
2013	7.481713649717632
2014	7.433251173017669
2015	7.498025583311789
2016	7.769527711140821
2017	7.886434060363589
2018	7.925011511678247
2019	8.03110035110267
2020	7.532614271955722
2021	7.388673048560809
2022	7.787039773606367