Year	% of expense
1998	15.946740981576097
1999	19.892596854622173
2001	6.5523006408943525
2002	16.056972918925354
2003	26.0257717943419
2004	25.785572324677293
2005	19.414842024544214
2006	9.554957818804255
2007	6.8433405256364805
2008	9.934123017372304
2009	9.381907599721483
2010	10.73307070825709
2011	6.436665582888636
2012	8.4321467103869
2013	8.941064701735147
2014	14.285766805387167
2015	16.89185572240635
2016	21.97308781170263
2017	22.831944804191785
2018	33.71810974230766
2019	41.996115735640345
2020	32.51321308755625
2021	26.531891649157597