Year	% of expense
1995	9.197764117923626
1996	12.160899202261668
1997	22.15528566843616
1998	31.05323913734947
2002	16.334353201832286
2003	19.214911694912995
2004	16.904273856866517
2011	13.668230177503284
2012	13.460802086563833
2013	13.223689849913809
2014	11.681541436375584
2015	10.987621509097783
2016	10.261405693611717
2017	8.583773750602099
2018	9.588226656293122
2019	8.948125685752123
2020	8.397996583351647
2021	7.865486076359657