Year	% of expense
1972	25.938796680497944
1973	26.704078839310224
1974	27.04203323558162
1975	26.91526800216575
1976	26.515550869794307
1977	25.757971392926528
1978	26.097368492666146
1979	26.424341433530657
1980	25.606057150676158
1981	25.553396417708647
1982	24.965844249778975
1983	25.14223151967779
1984	25.443951165371796
1985	25.847671153984574
1986	26.06928887731183
1987	25.886855241264595
1988	26.303649263465985
1989	25.188877879613624
1990	24.707414063937275
1991	3.8691079934111765
1992	4.035401485195896
1993	3.782393840142504
1994	3.404911655327244
1995	2.6187960945176894
1996	3.0614646368022447
1997	2.868164818739432
1998	2.842581963073114
1999	2.9626277190440473
2000	3.0007726126824887
2001	3.0010110749711973
2002	3.0637655752383823
2003	3.143504215488639
2004	3.147117431574488
2005	3.4692317131897363
2006	3.518932270501097
2007	3.59421013232046
2008	3.8227363414838385
2009	3.955485146945423
2010	3.8687007939210165
2011	4.336368472829609
2012	4.621774091041183
2013	4.688141353676483
2014	4.5592691432410675
2015	4.422863379562867
2016	4.717303195387523
2017	4.996399594229938
2018	5.028686230025731
2019	5.256066203523928
2020	5.388518015475357
2021	5.619567639028676
2022	5.694324507177581