Year	% of expense
2005	9.698272017049483
2006	10.413629539372048
2007	15.370866845397677
2008	12.209667621723087
2009	11.582778396698684
2010	14.96661352839998
2011	16.853667291494304
2012	16.62406389346132
2013	14.480704860255834
2014	14.912371281036926
2015	17.989861925901508
2016	17.284945587134796
2017	20.273235018271837
2018	20.729725278172126
2019	18.880409994516477
2020	17.589983923910125
2021	17.210609520928497