Year	% of expense
2001	25.431562949238717
2002	23.349754474057587
2003	17.1424078005819
2004	14.851169100630438
2005	13.27287716405606
2006	10.23988820743731
2007	11.32461161079313
2008	10.860349871634128
2009	10.085870320247192
2010	10.580331135563044
2011	13.194160267674457
2012	11.100039077764752
2013	10.24088457852351
2014	6.231305925676598
2015	8.167826550431807
2016	9.368574380561892
2017	8.325766621369638
2018	9.063054394845466
2019	10.80523213140541
2020	11.413475475755448
2021	11.866927603744386
2022	11.911585885852798