Year	% of expense
1991	2.1569951725324743
1992	1.5255356386000019
1993	2.099373369263014
1994	1.9819712065632764
1995	5.927414146917849
1996	5.166180948349048
1997	5.125403358461145
1998	5.451042660575347
1999	5.153972362486114
2000	5.176202605910972
2001	5.7187850563450455
2002	4.942109338241188
2003	4.913582334940482
2004	5.306287321288936
2005	5.509492953933455
2006	5.4999722734193925
2007	5.139328724268262
2008	5.247224492817782
2009	5.401355912654386
2010	5.358368665003973
2011	5.407501539448478
2012	5.66340426061111
2013	5.3765587184216175
2014	5.2143559023379975
2015	5.633519401925678
2016	5.472320398068302
2017	5.41065374681578
2018	5.20574678923742
2019	5.33153275235469
2020	5.1716514990049784
2021	5.2690347625810325
2022	5.5408141875154175