Year	% of expense
1998	0.20126954636940703
1999	0.5907172995780591
2001	16.193819330081762
2002	0.7899285241306799
2003	2.6211707301581897
2004	3.09221938853296
2005	0.6772242659672146
2006	1.9577576720870522
2007	1.0692424555060143
2008	0.7992654496272048
2009	1.2537821456107343
2010	1.1020922709563448
2011	1.365678572529901
2012	1.3721045153477325
2013	0.7423879551821967
2014	0.3690656375630371
2015	0.6168888504033871
2016	0.3050484191544513
2017	0.3944052214487707
2018	0.5869212896665128
2019	0.27548595498503914
2020	6.138792637871185
2021	7.557075517022612