Year	% of expense
1999	9.168186982039467
2000	9.418769269145516
2001	6.960725547015489
2002	4.200449314427046
2003	3.1720006193591352
2004	2.6830438166654074
2005	2.0521821757090257
2006	1.6867791219378683
2007	1.4829899567305784
2008	1.249121914332761
2009	2.6645437528239775
2010	3.755047124549449
2011	4.9426855341146245
2012	4.464115084668493
2013	5.84209806413713
2014	7.383734283864669
2015	11.6820063569338
2016	12.18393367494854
2017	11.127121055642244
2018	9.777390677034106
2019	9.122107323330086
2020	7.6826708996021145
2021	8.444151921343963
2022	5.2658556083583505