Year	% of expense
1990	13.964095099466277
1991	16.377875673029855
1992	15.73248407643312
1993	11.611124624989865
1994	14.28181321682141
2000	9.623856319891562
2001	11.335504885993487
2002	17.62176968400854
2003	17.47085438752931
2004	17.039680115513843
2005	18.235510398864673
2006	18.004767742474503
2007	18.442526709594137
2008	10.933181046764886
2009	10.838043267758772
2010	10.849964160410458
2011	11.947824917635986
2012	14.335907477216997
2013	14.97556102608013
2014	20.34506045793671
2015	26.093082233597897
2016	34.39750633379829
2017	26.126497921252138
2020	33.035714285714285