Year	% of expense
2001	39.126611023866545
2002	30.643994946959523
2003	24.94099521358822
2004	18.5123493881729
2005	16.003747662980103
2006	13.462831901091224
2007	10.636996592969513
2008	10.953536705822641
2009	15.64649484029506
2010	15.508764730068561
2011	12.74092990624709
2012	12.031739314940957
2013	18.3201934916469
2014	24.51310569803792
2015	28.47795552225959
2016	28.705466310591067
2017	29.757407861619672
2018	29.128630171560584
2019	31.664111246197784
2020	28.680304598127876
2021	34.99016474461621
2022	32.791876517600635