Year	% of expense
2003	26.94358047764529
2004	30.61714494498979
2006	30.80838991242872
2007	32.20411334088953
2008	34.50227675579343
2009	34.06834829521017
2010	35.42618604388785
2011	35.48293257347669
2012	35.5887568364776
2013	33.7068844259777
2014	34.0256717196802
2015	34.376865503299086
2016	35.297922002682824
2017	34.03122685570049
2018	34.978824919965156
2019	35.14475047242816
2020	38.29690807433083
2021	37.00333275132952