Year	% of expense
1990	1.0619310736352572
1991	1.1283854986382733
1992	1.4678425784896576
1993	3.5078567992259417
1994	1.720615509447085
1995	3.9066065222733175
1996	2.699332346501372
1997	11.080145298651624
1998	28.00556812879594
1999	32.79191861371631
2000	1.3367911899150555
2001	9.634353268072159
2002	29.565382204605406
2003	5.875981388781409
2004	6.96559155906377
2005	2.4936844936001132
2006	1.3142947309044888
2007	0.19821846202123047
2008	1.3889727640558005
2009	0.09050263206310812
2010	0.22916213633106833
2011	3.6266429225747894
2012	4.130381297064395
2013	8.81677747761186
2014	7.861941122784305
2015	7.312010147344317
2016	9.180036918057018
2017	11.010457577379198
2018	10.137821020614668
2019	9.451399449677172
2020	19.082406854886976
2021	24.07705143738534
2022	15.114626041910068