Year	% of expense
1991	2.551418901327774
1995	9.415392806481012
1996	9.509854806200611
1997	8.895441748106903
1998	9.444132846473806
1999	7.76640244277786
2000	7.356638559425575
2001	7.221777278581186
2002	7.4088169029979225
2003	7.799683309887391
2004	8.029911160863753
2005	7.830638239218901
2006	8.554654196185481
2007	8.253626641851389
2008	8.493637724730615
2009	10.173557484492255
2010	9.667467838570506
2011	9.768636517921399
2012	9.778732425010666
2013	10.119181141989168
2014	9.820135468452293
2015	10.374355319957635
2016	9.984010822433904
2017	9.684110820540884
2018	9.108248544317641
2019	8.672543411155791
2020	9.217144580550652
2021	8.760917607388635
2022	8.959565750860227