Year	% of expense
2003	25.368219291965914
2004	31.24366910523354
2005	36.42906235407779
2006	39.6019548390939
2007	41.81996636850289
2008	42.2553979765404
2009	40.45122218683716
2010	40.18585713646805
2011	35.729046805713274
2012	39.162448958936395
2013	40.252215004947374
2014	39.05997136400936
2015	40.88926011527883
2016	37.88351086491179