Year	% of expense
1990	8.283132079573459
1991	2.3454921949665475
1992	13.339152636179277
1993	6.620023567864615
1994	14.197510351382068
1995	1.0110736639383726
1996	6.235708547061368
1997	0.1763396301276258
1998	3.129428716062717
1999	5.9991892987434134
2002	2.0426967346687306
2003	2.4647940730774516
2004	9.24790439089731
2005	13.429735104410797
2006	11.582910216179698
2007	3.1223704695713903
2008	3.0002410739198875
2009	3.696702741578666
2010	3.1502779527510896
2012	2.674845513124785
2013	1.6344157596305353
2014	1.6673497660828884
2015	1.1829430869500246
2016	0.8178162768881712
2017	1.6523467834262622
2018	1.0827827007069424
2019	0.9700025237945239
2020	0.508084736979081
2021	0.8202336305542574
2022	0.6782075595156396