Year	% of expense
2004	9.305654498297262
2006	8.910494211391805
2007	6.53747564980431
2008	6.181049900891192
2009	6.041120713025364
2010	6.1283410102752915
2011	5.7085879628572265
2012	5.965924140398362
2013	6.045520476204295
2014	6.231305925676598
2015	6.6216098716900635
2016	7.563168150165953
2017	7.697914458524695
2018	9.432469162936544
2019	8.038446477337894
2020	8.117593405040427
2021	8.365780803394994