Year	% of expense
1972	6.052009456264775
1973	7.086614173228346
1974	6.715063520871143
1975	5.682242990654205
1976	4.963072378138848
2003	6.877457909863797
2004	6.919692718622715
2005	6.216758504211388
2006	4.39059370681731
2007	2.737004807142737
2008	2.8096075129544427
2009	2.7275926614640804
2010	3.752261991492562
2011	5.393193557275785
2012	6.522968493485065
2013	8.644287736177832
2014	7.529923544375265
2015	8.172478172923627
2020	9.952225710597263