Year	% of expense
1998	2.4650218715062575
1999	3.829291303623952
2003	10.490047183213946
2004	7.467730397438597
2005	5.299883701611564
2006	7.027142551827313
2007	7.645998517184887
2008	9.010792586026653
2009	10.264336939786507
2010	8.284083899216489
2011	9.27960649009649
2012	8.36827039122189
2013	8.717797432640722
2014	8.010360960901453
2015	7.495568758693589
2016	7.8351887915489185
2017	8.136907509947218
2018	7.627857551575707
2019	6.730437958898677
2020	6.691243036056012
2021	6.549892590369431
2022	7.6713586215971885