Year	% of expense
1998	11.116857011800523
1999	8.57713742014408
2000	2.592298681177493
2001	3.073135972015288
2002	2.8427276503212884
2003	2.6294927476339818
2004	2.928709055876686
2005	2.6689708156947964
2006	2.7727401560090295
2007	2.8015453031276656
2008	3.4234040463682556
2009	3.2167059370127746
2010	3.523285238327335
2011	3.662760252763022
2012	3.032604722567439
2013	4.200485588723315
2014	4.078174635385171
2015	4.336560872847693
2016	3.4045283218494684
2017	4.706041660471622
2018	3.9814891118135916
2019	3.305635775078355
2020	4.555459545912574
2021	4.0325347249413905