Year	% of expense
2001	22.916820534748048
2002	17.92189564796908
2003	18.923495861162667
2004	14.452413254730521
2006	20.33247081360843
2007	23.0642765400734
2008	21.466309139151107
2009	16.236268266967976
2010	15.919023223016138
2011	16.088914942201097
2012	16.474141066006524
2013	16.954441833083255
2014	18.232031148037628
2015	21.456717315623298
2016	20.650468407689303
2017	17.636274221047437
2018	16.79950825640025
2019	17.847979287936226
2020	15.30752986019289
2021	13.943365980748474
2022	19.243170271830667