Year	% of expense
2005	39.26521523674819
2006	43.008392655733935
2007	41.94276244014219
2008	60.478564779020786
2009	63.94951516084346
2010	65.12294303196138
2011	66.57746656854655
2012	68.79408825310213
2013	68.6992720952299
2014	69.80700906439043
2015	68.2555045739689
2016	69.42720602504548
2017	70.72431470356803
2018	72.57489956350335
2019	72.09528999145127
2020	75.54313847295514
2021	73.23788057024868