Year	% of expense
1994	17.38039106919983
2004	22.229683268674076
2005	23.113116649537513
2006	20.435918424314455
2007	17.38599655975694
2008	19.383286667463864
2009	17.225491787988396
2010	22.611193045736062
2011	24.245089129393282
2012	26.36373997204513
2013	32.088601763523435
2014	39.941374166559996
2015	41.234609378995785
2016	35.93015669830688
2017	38.992930448975585
2018	34.92164007379314
2019	39.06622223402605
2020	35.69850878502393
2021	40.94192448224172