Year	% of expense
1990	5.43456045462476
1991	3.0627049234878365
1992	2.465524941800489
1993	2.6936587099628317
1994	2.2973613639406913
1995	14.519061408014014
1996	14.411208244362115
1997	14.100556212765827
1998	14.137144371016882
1999	15.036524183932773
2000	15.244821543656691
2001	15.903483704761157
2002	16.182661216521264
2003	16.049515399942823
2004	15.211924743236283
2005	15.560631660421171
2006	15.28671836871373
2007	15.38438215363158
2008	18.539939621906534
2009	16.869494463508687
2010	15.323677592504456
2011	13.991498280218712
2012	14.776597592853708
2013	14.189878915081364
2014	14.104244558049292
2015	14.419195004411863
2016	14.429708866372914
2017	14.372492169095757
2018	15.390139504015988
2019	14.359776519953488
2020	13.757628181691176
2021	12.999993991359576
2022	13.316605704388806