Year	% of expense
1990	7.059650108901848
1991	7.8409124544907405
1992	6.518406628330429
1993	5.762153872571224
1994	5.236362309244381
1995	5.442747958095038
1996	5.157366801540959
1997	5.0583914215212475
1998	5.292261883662401
1999	4.979967222922047
2000	4.027617230041159
2001	4.209348217942568
2002	4.0114198569591375
2003	3.673329025514683
2004	4.580809099338086
2014	4.548582023453621
2015	4.648594562923591
2016	3.8992857100745253
2017	3.9511068142784747
2018	3.6541800523563075
2019	3.6546974581600193
2020	3.262213077902772
2021	4.421977450428859
2022	3.591896216436203