Year	% of expense
1990	19.605756086362167
1991	25.14559875755727
1992	20.640328641176325
1993	19.972043113903755
1994	33.90234711491673
1995	25.50334025176058
1996	20.3232050174862
1997	22.59752848108148
1998	29.00786110800641
1999	25.319281226225275
2000	23.95154169511086
2001	22.0899133478099
2002	16.39826868741156
2014	55.22025332753932
2015	50.67865594873836
2016	48.003628073375154
2017	41.698204749079046
2018	41.9867843864493
2019	37.852620470201394
2020	46.635912724096116
2021	44.55444705625893
2022	44.11153923638624