Year	% of expense
1992	25.082825691995296
1993	22.243911228565423
1994	30.363873719822752
1995	29.614287029365737
1996	26.75282944041651
1997	26.630210008731215
1998	27.40189328247705
1999	24.581732768955984
2000	23.11562923041557
2001	28.97561960987466
2002	26.13637562429494
2003	35.884405443959
2006	25.719835415854586
2007	37.162236885263475
2008	26.208767017993654
2009	19.6151498446671
2010	20.182187818373848
2011	19.021556549472347
2012	15.811765889296744
2013	12.882945029284167
2014	11.459334027774755
2015	11.14675216744495
2016	13.900288547819711
2017	12.153046308877103
2018	13.774551606512238
2019	15.108379686065723
2020	14.871841933189533
2021	11.794625764537452