Year	% of expense
1990	59.64428613252659
1991	59.70415859154272
1992	62.517812061711076
1993	66.45060593106602
1994	66.25452268940056
1995	66.79541065545837
1996	64.39541178715554
1997	66.6059369049739
1998	65.50042819725829
1999	69.01460349475398
2000	70.02827637078927
2001	69.08112703283395
2002	67.04290463328485
2003	67.43019985821664
2004	57.72197950958373
2005	39.41479665598089
2006	39.54778669442713
2007	25.974310319661363
2008	48.75390361888433
2009	49.76815466834329
2010	52.13047950625099
2011	47.34831572158556
2012	46.03108520677213
2013	48.27543231032871
2014	45.717742271911895
2015	48.07665010645848
2016	49.541910730621666
2017	49.69406404789024
2018	46.82196586052716
2019	48.434353786609115
2020	47.44533064802206
2022	45.25887143688191