Year	% of expense
1990	8.264900662251657
1991	10.508695835263401
1992	11.052930909376164
1993	10.573644769709453
1994	9.009514741098139
1995	10.421138886965354
1996	8.141819868750945
1997	8.324641845088161
1998	9.06559308187739
1999	10.671217583241718
2000	9.190146447422125
2001	7.556042237929995
2002	7.334378328853466
2003	9.172780424542205
2004	8.861157040061334
2005	8.209938974045295
2006	8.672586022681925
2007	10.335108703682279
2008	9.726908284564848
2009	10.858584114284474
2010	11.057368797030051
2011	11.33640671459542
2012	14.5285484371078
2013	12.132414087209922
2014	11.466438586589272
2015	12.15158615105235
2016	10.802016593735662
2017	10.966345095312404
2018	9.79066138880727
2019	8.71214604509693
2020	9.808550840688032
2021	9.520164356832511
2022	6.562929619938799