Year	% of expense
2001	20.39499712095514
2002	23.139039943457828
2003	32.42903200440355
2004	34.83361264065118
2005	31.702016038372182
2006	33.63092927567736
2007	31.84791496320523
2008	34.93939936712639
2009	21.27458142710005
2010	20.222626326420613
2011	18.00658353994656
2012	18.51766600901648
2013	17.974652762877454
2014	21.368996011917883
2015	16.94349130236849
2016	16.974053430740966
2017	16.276071014933777
2018	13.073409987536836
2019	11.875613566159519
2020	13.65749331971792
2021	17.439415803987472
2022	17.734989562516496
