Year	% of expense
1972	6.896551724137931
1973	6.971428571428598
1974	7.136150234741775
1975	6.496985934360362
1976	6.189451022604956
1977	6.366530241018631
1978	6.034801925212895
1979	5.990922844175485
1980	5.933395872420263
1981	5.668389955686855
1982	5.263921113689094
1983	5.559845559845556
1984	5.387931034482773
1985	5.246612466124662
1986	5.702393340270572
1987	5.271408975112692
1988	5.027000490918022
1989	5.299373523672609
1990	4.814641013608643
1991	4.824103099965179
1992	5.003238341968927
1993	4.551579577781105
1994	4.495412844036699
1995	4.288588756447814
1996	4.213616903745175
1997	4.488728708919453
1998	5.248664753728618
1999	5.400813604220082
2000	5.9323125323697266
2001	6.31030261193743
2002	5.844169889066842
2003	5.903668440743469
2004	5.920282511074027
2005	10.989277207678867
2006	11.072765678143929
2007	11.571177651760626
2008	11.011962579598052
2009	10.638619573797701
2010	6.9635577606098735
2011	9.34395357234556
2012	9.686282672693212
2013	10.036367611601161
2014	10.51366003755726
2015	10.739008165051725
2016	11.525420511939478
2017	11.82644462034078
2018	11.705317475669926
2019	12.78964533656129
2020	12.853756622741857
2021	13.664368206768104
2022	14.96158085004453