Year	% of expense
1992	0.6626055359623811
1993	6.090272981170606
1994	3.1349403350065272
1995	2.3645138806696386
1996	3.9993492032824562
1997	11.902683043715165
1998	6.391988983700256
1999	8.46468155905165
2000	6.637670265674658
2001	5.3592548065175105
2002	5.9576780413222705
2003	3.9224403427074614
2006	1.922867660972773
2007	1.614875414003351
2008	1.188669879337604
2009	1.698697289766823
2010	1.8757506964206578
2011	1.1595976128985312
2012	2.7867046753728886
2013	5.942090195200661
2014	9.484977606610295
2015	13.132500495883267
2016	15.039245078117983
2017	17.41936668027141
2018	14.376148973018932
2019	9.081173661598264
2020	7.8734332957599555
2021	6.00938844942534