Year	% of expense
1999	3.9467869394979727
2000	3.378102824828036
2001	5.256119757809889
2002	3.2824392914682172
2003	3.977267774804536
2004	6.195303284708536
2005	4.259509135334233
2006	5.31145781239902
2007	6.635679599501427
2008	7.3600550075305655
2009	6.576694824613331
2010	8.269612138541715
2011	9.027360775039853
2012	9.008072492721867
2013	7.983303875013892
2014	7.861941122784305
2015	6.73877648209643
2016	6.405356060485717
2017	6.244434253690741
2018	6.965034598482767
2019	6.573430296657087
2020	5.849421294269758
2021	6.241864293859475
2022	8.835499151040175