Year	% of expense
1980	9.707059230351232
1981	10.018537922140727
1982	10.30686038178383
1983	10.199377665091607
1984	10.13467856560337
1985	10.135759817040542
1986	9.411793582465494
1987	9.87046724860441
1988	10.002432556620663
1989	9.80842076451398
1990	10.842653461965359
1991	9.003358356380877
1992	9.33288826818845
1993	9.807611892405355
1994	10.73767505160907
1995	7.56226424891733
1996	7.033646716228925
1997	8.501841476986208
1998	7.670318647336018
1999	7.458535612287106
2000	7.886687710586354
2001	8.023738637302635
2002	7.992641582948154
2003	8.018692057386001
2004	8.484411536012075
2005	8.927753409138507
2006	10.071248415614896
2007	10.135839026521555
2008	9.597038724910684
2009	9.40369137556126
2010	8.965002987378636
2011	8.524029330894635
2012	7.840577725373353
2013	7.973165287121462
2014	7.851775809376507
2015	7.93251325507684
2016	8.24806907324719
2017	8.109958575142379
2018	8.229396662852071
2019	8.064154472294058
2020	7.618182746443301
2021	8.116468960918517
2022	8.163269587551596