Year	% of expense
1990	0.4417311329837239
1991	0.51655684203962
1992	0.6042442113404554
1993	0.30833310794363455
1994	0.20839738990810017
1999	5.262708805093368
2000	6.093586128503514
2001	8.823068823068823
2002	9.024611665337526
2003	7.877017574454068
2004	7.307824420580684
2005	7.311452395852713
2006	7.901947864099515
2007	8.015880766543718
2008	7.987355184095693
2009	7.515403116866001
2010	8.557672708063585
2011	8.184892224840485
2012	8.701763874503161
2013	8.132774659605326
2014	8.369627595863289
2015	8.359884516730121
2016	7.972318400976366
2017	7.911460680877788
2018	8.474057087033822
2019	8.242829677874996
2020	7.245861937833997
2021	6.52434527359968
2022	7.370209201126289