Year	% of expense
1999	0.12468751469166413
2000	0.06784874838786457
2001	0.6810852557791286
2002	0.6930855335398332
2003	0.6450034380034566
2004	0.867313440596874
2005	8.558667546825397
2006	3.4406553629262717
2007	14.97561804656757
2008	7.172753662323634
2009	9.228287562396673
2010	9.096860703581006
2011	11.413020247068378
2012	9.882147321916229
2013	7.76602260704939
2014	4.651212372326061
2015	6.6962818275380105
2016	6.405356060485717
2017	6.279154288833453
2018	7.043207937333536
2019	6.98999236419232
2020	4.885120729843349