Year	% of expense
1995	12.935795766077804
1997	15.862182490439892
1998	16.092940167123064
1999	17.6644626246778
2002	22.200263647837783
2003	18.98808529606149
2004	25.80725348570732
2005	24.29024215617505
2006	20.832370716718135
2007	24.24565778271108
2008	28.70178189540953
2009	21.895086383724077
2010	25.69286135961761
2011	32.17376985652289
2012	35.792279188758705
2013	31.74483179019012
2014	29.084241802562193
2015	24.631486987412153
2016	23.293746103308937
2017	25.32964331395093
2018	26.718203253585322
2019	27.61150723603587
2020	32.591861665328345
2021	28.76102538699718
2022	34.21656030139015