Year	% of expense
1990	1.1510695187165776
1991	1.4248627178867526
1992	2.715520859565181
1993	2.859858046506103
1994	3.5614612404715293
1995	2.446060551137694
1996	2.2381000301901985
1997	2.4222067087057533
1998	3.439614517121181
1999	6.90672963400236
2000	5.179914616792031
2001	5.256119757809889
2002	2.000641917192682
2003	2.9363160584880044
2004	3.270526561363543
2005	2.7160532222032168
2006	4.091662786990892
2007	4.726745081925111
2008	5.8739995591525584
2009	9.701945427272623
2010	10.475420788027249
2011	8.866897942240408
2012	9.008072492721867
2013	10.008351699674852
2014	9.43463164423977
2015	9.60918584444047
2016	9.098939229480255
2017	11.737652379008107
2018	11.047184436340496
2019	11.0410081869052
2020	9.40482927168122
2021	19.03269540782024
2022	17.22927906899067