Year	% of expense
2008	15.640987842063204
2009	15.401587143822896
2010	14.975056609272098
2011	15.830655689460075
2012	16.300989130997664
2013	15.987302926093239
2014	15.738000542496746
2015	16.326394884736104
2016	15.949852237105656
2017	16.13561779931302
2018	15.753200328349775
2019	14.321898218266996
2020	15.146689720949492
2021	15.846374841039301