Year	% of expense
2008	27.517182542594153
2009	26.93992630924732
2010	27.73188695676397
2011	28.599825567036703
2012	29.153543531903637
2013	28.198411261463146
2014	27.68599349214928
2015	25.832539397168425
2016	28.093925772893247
2017	24.760789152910963
2018	27.09734738985648
2019	32.882475889789
2020	25.876343014231317