Year	% of expense
2004	3.040073379221492
2005	2.4405668401996916
2006	1.9813083321191467
2007	1.8551337447639558
2008	1.465410252818674
2009	2.1718687422457186
2010	3.824796305876024
2011	4.167476865201937
2012	4.459573934804112
2013	4.5328559069607195
2014	5.3220868966410135
2015	5.857185533165551
2016	7.543021343692261
2017	9.697223445212382
2018	10.465076384510668
2019	11.066212824196347
2020	10.027046029992444
2021	10.358688005576342
2022	11.022643996270553