Year	% of expense
1995	6.079651090087066
1996	5.189880353927862
1997	3.3161567833223535
1998	3.7457755569909734
1999	3.9269292956073447
2000	4.000174082675973
2001	4.342916203325051
2002	4.300693644058003
2003	4.205996953797744
2004	3.883025812708402
2005	4.005998776647755
2006	4.228984289902528
2007	4.11714906032327
2008	4.012296900716341
2009	3.8102716163286683
2010	3.672681928190327
2011	3.253593257063371
2012	3.778054986900966
2013	3.8169884014969226
2014	4.039891430540232
2015	4.259504111113027
2016	4.5123354258671275
2017	4.321606260981408
2018	4.08744252789919
2019	4.138992570973311
2020	3.3746386074147128
2021	3.618289280727189
2022	3.2299937658412587