Year	% of expense
1990	14.443226377703757
1991	14.26227465315278
1992	12.174599472541667
1993	10.257036887956069
1994	10.15670503397587
1995	11.829986919996225
1996	10.43518196713172
2004	10.103822677996893
2005	10.28471865364851
2006	10.013713758170278
2007	14.575051999369904
2008	14.01792151298952
2009	14.297308458842211
2010	15.183431098926963
2011	17.16537442165445
2012	15.76043522130181
2013	13.846671828068203
2014	11.309956626273292
2015	11.242939577636477
2016	10.133368592904775
2017	9.953165015534998
2018	9.508955791863476
2019	10.65456484244515
2020	12.627214177180882
2021	11.757989804518061