Year	% of expense
1991	0.26034886748242614
1995	1.2130900883957119
1996	1.5804597701149428
1997	0.8870184525736483
1998	1.0246804759806083
1999	0.7035577067012624
2000	0.5392013990090353
2001	0.4524266520427749
2002	0.5653710247349824
2003	0.5170361553340277
2004	0.5112098633432457
2005	0.40233766996563974
2006	0.32361653929451595
2007	0.25032855623005196
2008	0.24739880336181636
2009	0.23099100350828441
2010	0.2095347254557828
2011	0.22975797674780174
2012	0.32881283842366144
2013	0.3290947576595646
2014	0.4165685350918512
2015	0.3472222222222222
2016	0.3040591901890235
2017	0.2310242874756108
2018	0.17319016279875304
2019	0.14448995047482388
2020	0.23132555748573047
2021	0.2256519066744129
2022	0.2424932359201878