Year	% of expense
2004	17.059005654209187
2005	20.45192273356012
2006	21.297322025321378
2007	21.36591100136604
2008	21.011127008083076
2009	24.799313718969398
2010	23.595311347284575
2011	23.552351524001903
2012	22.288019054762703
2013	21.755151629901366
2014	21.596288748481523
2015	20.990967438082418
2016	20.755660404470596
2017	21.73025212496703
2018	20.739097878848792
2019	21.160253014392797
2020	19.205150749598545
2021	18.40959396427516
2022	19.068284067506884