Year	% of expense
1993	66.19103843841567
1994	70.3963397933155
1995	31.68379295765501
1996	36.48661451523804
1997	44.11758325825424
1998	43.90668133097982
1999	46.55369810339288
2000	47.81227074693456
2001	43.93390571639663
2002	43.84628746946263
2003	42.13232484798249
2004	44.12124599036281
2005	44.282501222756174
2006	45.25485876506189
2007	45.78509101013199
2008	46.1443683691093
2009	46.75824619950231
2010	46.84749237472611
2011	48.531170307295426
2012	48.55351542015025
2013	51.667483225790754
2014	50.94303348780205
2015	50.900526677769676
2016	51.12714981280304
2017	51.011999306099796
2018	50.263677461443876
2019	50.28694267718472
2020	51.3369208203391
2021	51.58871668660235
2022	50.51703695344999