Year	% of expense
2009	35.718456940675345
2010	41.352958839401516
2011	40.589213386534716
2012	40.84713441255172
2013	37.79305251998342
2014	37.352512354057325
2015	36.40675007283936
2016	39.90890429466968
2017	40.62732242230727
2018	36.5902610040963
2019	41.48166192936324
2020	37.78358692104879
2021	38.55764390739705
2022	34.9223995616018