Year	% of expense
2003	30.268150124988324
2004	29.255068360566128
2005	34.43493950369382
2006	33.03829172839611
2007	33.92514452609319
2008	31.982837504870485
2009	32.932141503128136
2010	29.206010646150887
2011	27.62877448404194
2012	28.654029519277618
2013	27.400837987987924
2014	27.81810683499068
2015	29.10171982424716
2016	28.636830728857305
2017	28.51041762940902
2018	26.777301033068554
2019	27.07615050697263
2020	28.64772243607015
2021	25.939147948207648