Year	% of expense
2001	35.81593600923571
2002	45.97831541407251
2003	41.6856674463901
2004	39.67417786624111
2005	40.114201125989645
2006	42.25660807332044
2007	37.514855763372815
2008	34.630748603875105
2009	39.94597678451391
2010	35.72511665426649
2011	38.39500244231367
2012	35.449062697443544
2013	39.494945122392174
2014	36.234856691684364
2015	38.004267547640595
2016	35.268308476140334
2017	36.782565452635104
2018	36.10657945312995
2019	35.587870798604996
2020	32.958784118281464
2021	33.04947058475814
2022	28.303643849099064