Year	% of expense
1983	7.90036723614881
1984	7.893886424395546
1987	7.117883924480988
1988	6.244577377962464
1989	6.112448958224269
1990	73.12567644415094
1991	74.4386276833926
1992	75.48099590868303
1993	74.52414414168565
1994	71.2202557599957
1995	61.84252333110839
1996	60.12354974284888
1997	59.5230203611257
1998	60.613448721651295
1999	61.09530246909838
2000	61.33539831202421
2001	63.620993993167666
2002	63.38204191501634
2003	64.93006666849571
2004	65.26663102586119
2005	65.79740499622747
2006	66.45189532702041
2007	67.74418195832375
2008	68.82931691651409
2009	69.6091883114581
2010	70.76397758947155
2011	70.351707364562
2012	70.9498392722351
2013	71.59943296281604
2014	72.16910280958031
2015	72.41865163565924
2016	72.45603101916153
2017	72.94972505354724
2018	72.68700366269738
2019	72.32085334983691
2020	73.8105788249912
2021	73.20274410838995
2022	70.12639159815343