Year	% of expense
1998	0.030499660691274813
1999	0.39528644260876605
2000	3.2015140387548726
2001	1.8147662425123172
2002	27.348691917219835
2003	21.949414479125853
2004	26.95264623955432
2005	5.299883701611564
2006	9.892640164230034
2007	11.11715217764551
2008	14.818072966302568
2009	18.00641673625456
2010	11.682830459770114
2011	14.500762376695409
2012	7.564059506114866
2013	15.940280798892626
2014	0.18896499938642278
2015	1.1324266970404744
2016	7.9808428454161096
2017	12.54385307152235
2018	14.040595567436512
2019	12.362521786165034
2020	16.464524670780435
2021	14.196198322034096