Year	% of expense
2004	32.15298264789596
2005	36.478729984838786
2006	37.203866457749804
2007	34.89490124203394
2008	43.203632521686075
2009	37.36575579597511
2010	38.97623043229051
2011	35.99583669852559
2012	37.1509682135502
2013	36.893191753900325
2014	40.94839482338172
2015	37.27631779879988
2016	46.09492962370758
2017	38.47261915340514
2018	40.21123352959293
2019	38.187381840205944
2020	41.130239430388926
2021	42.06592824292157
2022	39.77743210603805