Year	% of expense
2009	33.884697261523755
2010	33.05382907955841
2011	34.00584094248524
2012	33.18455672352974
2013	31.91857520382851
2014	32.74992732338411
2015	33.42460605734488
2016	32.5074766551749
2017	32.20268822314461
2018	31.951999905969302
2019	32.11503291816846
2020	34.789580875124976
2021	35.18230586462858