Year	% of expense
1992	20.60557341907826
1993	20.72880424830621
1994	18.866316238102016
2002	18.0139139882285
2003	18.324075895994376
2004	18.519214658845407
2005	18.317786850938646
2006	18.493093603048873
2007	18.74275513471334
2008	19.16128568986955
2009	19.254037528098202
2010	19.169403578454375
2011	18.7378166232918
2012	19.18746068484886
2013	14.543648199605922
2014	16.62984575527512
2015	16.789749465963556
2016	18.035423822447385
2017	18.829776744488086
2018	19.078509871934006
2019	19.52409005572541
2020	18.44146922613115
2021	18.669150933057825
2022	18.039130888324767