Year	% of expense
1991	76.72481124707087
1995	52.9245815309385
1996	54.333030852994554
1997	54.7491097442538
1998	55.00771264874395
1999	55.40641684546679
2000	55.45030603322646
2001	60.23215428205832
2002	60.18707129494908
2003	59.514953131974416
2004	61.21487520465101
2005	62.13033391089836
2006	62.694481093326026
2007	63.25802615933412
2008	63.63588510869755
2009	64.25023446455243
2010	63.96002722160535
2011	63.18171610206092
2012	62.94230234422288
2013	62.96525191971942
2014	62.20560527555347
2015	62.459781209781205
2016	62.76668524806163
2017	62.825439005997055
2018	64.39102009005889
2019	64.583021932578
2020	66.4179104477612
2021	66.31976895939108
2022	64.70826738193074