Year	% of expense
1972	12.017634854771805
1973	11.985582626152075
1974	11.745845552297151
1975	10.845289658906369
1976	10.266985022791376
1977	10.073403545420232
1978	9.90557052276381
1979	9.766183377578077
1980	9.446053501790242
1981	9.274670496789463
1982	9.001044764124407
1983	8.991378130559735
1984	8.62375138734738
1985	8.685479807069319
1986	8.72623078926806
1987	8.682196339434292
1988	8.502752060068088
1989	8.541305424820433
1990	8.205142719669398
1991	6.426334196155438
1992	6.4167068586624225
1993	6.307820490719991
1994	6.121060478826412
1995	4.883516426810935
1996	5.821746949720161
1997	5.790126626156933
1998	5.703520861156641
1999	5.744480682555247
2000	5.676191716797526
2001	5.661446615695894
2002	5.647621240539129
2003	5.598571299162958
2004	5.634492811304532
2005	5.588259813371204
2006	5.639755381268993
2007	5.6443213838522786
2008	5.709708613980682
2009	5.675111519562968
2010	5.51860088647486
2011	5.759855982018231
2012	5.826647874492608
2013	5.816611774609197
2014	5.813383968116397
2015	5.795588389030135
2016	5.7810315095451275
2017	5.756365334163246
2018	5.82633406140195
2019	5.829220411012757
2020	5.437737686210891
2021	5.212987057386609
2022	5.2404690845397806