Year	% of expense
2001	13.942042364550536
2002	14.269671180252258
2003	16.086532452307505
2004	16.912337086375548
2005	16.86775423719151
2006	14.549126227243518
2007	12.951661867330518
2008	12.424536733461867
2009	12.435155332195789
2010	13.476470345839358
2011	12.910012109396535
2012	12.51608431143612
2013	14.28557892725463
2014	14.84094894724462
2015	14.632132215175272
2016	13.811674029053348
2017	13.738852192168736
2018	15.753200328349775
2019	16.997115304090034
2020	15.421537508709452
2021	14.766788045766683