Year	% of expense
2001	39.96905830100546
2002	36.11738937322713
2003	33.695961416010725
2004	36.70713854029231
2006	37.591998436604776
2007	35.312375107551944
2008	37.43423297279956
2009	45.07282754944774
2010	41.721532936448206
2011	40.691133165119766
2012	38.230594382505906
2013	38.02337636575281
2014	42.47643544926623
2015	38.76925578769846
2016	37.674076998282466
2017	35.91011669207977
2018	36.26572628832127
2019	37.852620470201394
2020	43.90099890313036
2021	42.663276810667625
2022	38.64807958937106