Year	% of expense
1995	14.289445731102097
1996	13.506184561064993
1998	10.656151389754601
2002	30.571312121322293
2003	29.351877855824053
2004	29.673900428133837
2011	26.606183783257855
2012	26.878818918257007
2013	25.592942788844695
2014	24.871307657521747
2015	24.47075392544819
2016	23.064614784857635
2017	23.784723803056604
2018	23.529298385535604
2019	23.878478698486383
2020	23.24979235587883
2021	22.72288323267497