Year	% of expense
1998	10.284186773864713
1999	9.202669315290755
2000	7.809186791177271
2003	9.002280692422863
2008	10.685857257364432
2009	10.51684844031921
2010	10.539530585129368
2011	10.029528254400134
2012	17.974269731324352
2013	15.22662601368658
2014	13.315881080496716
2015	14.313767551883283
2016	10.009661409419563
2017	13.09216649784675
2018	11.107124689912057
2019	9.193991367809147
2020	8.16463502954894
2021	8.006483911572456
2022	8.58235476558644