Year	% of expense
1990	6.236927172466249
1991	6.497331124608871
1992	5.620775524724298
1993	1.4100185528756959
1994	0.32229185317815573
1995	0.25184687709872394
1996	0.18212171801487326
1997	0.23887106723377466
1998	0.24500995481048965
1999	0.23069169711477888
2000	0.6950277576635289
2001	0.3690888119953864
2002	0.5635634550774901
2003	0.4604604604604604
2004	0.5423495809739968
2005	0.6429662198813784
2006	6.349221072941033
2007	2.6901858212129484
2008	3.5390755577761523
2009	6.037917658684804
2010	11.417499466992332
2011	11.1302589586287
2012	15.700753646673876
2013	13.177385435339414
2014	12.885831358205872
2015	13.660020822427068
2016	9.729050804282894
2017	12.660082306792217
2018	10.593744545222433
2019	9.533196319125956
2020	14.438669884291077
2021	11.656866035266717
2022	12.352744877892528