Year	% of expense
2005	37.28956877871617
2006	35.792863840464406
2007	34.9549990178889
2008	35.11461619328757
2009	40.489812740342195
2010	41.345957923178744
2011	40.58586593861078
2012	42.210408842960554
2013	43.13044020828887
2014	41.84061420511674
2015	38.300208873406135
2016	38.497622474457714
2017	38.20679000552624
2018	41.90543512209174
2019	39.710531271385236
2020	39.8532652929836