Year	% of expense
1991	17.31917415678471
1993	18.90786551275178
1994	17.93508261877599
1995	12.20867413512541
1996	11.786396252461685
1997	13.931493906576213
1998	12.919603221529783
1999	11.546705197173939
2000	11.640914234974296
2001	12.376131616698807
2002	10.52724390632678
2003	10.047027406886858
2004	10.038415629544685
2005	10.109057123168366
2006	10.837597618831746
2007	10.545069837128297
2008	10.708612736727368
2009	10.029023385184493
2010	9.851666346024517
2011	10.324023689690119
2012	10.413026354481628
2013	9.87271427691859
2014	10.184020676558234
2015	10.177022747159251
2016	10.22195411501107
2017	9.846721735318958
2018	9.348729955073232
2019	9.706690800886737
2020	8.736917076366602
2021	9.066934076538432
2022	9.716913999162808