Year	% of expense
1972	3.4531103956797162
1973	3.168794073016158
1974	2.6818062973891617
1975	2.0979634831460716
1976	1.999150361096539
1977	2.0738097892741734
1978	2.2748394727948735
1979	2.1981961583456053
1980	2.077829103243738
1981	2.048962617815352
1982	0.9777801460009625
1983	1.0293598744327
1984	1.3047725369801861
1985	1.5564336419398526
1986	1.5225387980758756
1987	1.6161453726783008
1988	1.200894821082582
1989	0.9933357348703171
1990	0.6300678952473321
1991	0.4376812000168085
1992	0.279941206247751
1993	0.48171125396513426
1994	0.44801330526753413
1995	1.0899172583572094
1996	0.8916748148721112
1997	0.7949524352512416
1998	0.8926761558553881
1999	0.9370994639033429
2000	0.7735234406510343
2001	0.671615823346256
2002	0.5689436365719241
2003	0.4893649857327571
2004	0.37456340784219677
2005	0.37859235616280273
2006	0.42989889642407125
2007	0.5767988756658265
2008	0.7414947023822499
2009	0.8229064829453817
2010	1.0249563957473595
2011	1.2396960383599323
2012	1.1627560739067944
2013	1.2574845427146895
2014	1.0418347113315636
2015	0.9868320323420529
2016	0.9919204241887182
2017	0.9667869865159209
2018	0.8932844769302015
2019	0.8235375477391775
2020	0.5174172832087595
2021	0.39103138837339885
2022	0.3792613297412915