Year	% of expense
1990	4.887593551841829
1991	5.352555512442548
1992	4.368650836242873
1993	2.6302391204922206
1994	4.162544543127276
1995	1.97747268399688
1996	2.8443127958877277
1997	1.6545525017907599
1998	16.007493382759613
1999	15.624064805471813
2000	15.217109408618676
2001	10.956269925830608
2002	10.251406037367946
2003	10.255097924455379
2004	9.701198020828224
2005	8.900230571838069
2006	8.530377601516246
2007	8.384427059024457
2008	30.946812904273322
2009	9.470317756090578
2010	12.96195456662979
2011	11.802158978627967
2012	9.766588219922824
2013	8.765043179911839
2014	13.084339656317306
2015	10.791407349262082
2016	21.747445501395337
2017	9.123096355499051
2018	9.229357115254546
2019	9.106627043759604
2020	11.266395721626397
2021	10.317240088716755
2022	8.932566832675478