Year	% of expense
1995	36.206896551724135
2002	33.98831610861094
2003	36.00130960495117
2004	32.64875227190777
2005	35.40028200728287
2006	36.018838420828395
2007	34.30933537743315
2008	34.29818595771841
2009	33.18379607875486
2010	34.22127582383539
2011	32.64809322376969
2012	31.63636942972922
2013	30.104908595089245
2014	29.3496973545503
2015	29.18050007366684
2016	28.554455616458835
2017	28.498504820988707
2018	26.96176035532538
2019	26.69946741875832
2020	25.049856539574577
2021	24.18905299024406
2022	22.081264580888075