Year	% of expense
2008	34.29258434064831
2009	33.94526196777319
2010	33.25182410192044
2011	38.34574927177255
2012	42.10876553023389
2013	36.145237010617635
2014	35.25880305509703
2015	30.774921183102226
2016	30.020355976206588
2017	29.72909332260414
2018	26.514386028286374
2019	24.18478291537471
2020	20.701794047868052