Year	% of expense
1991	18.19838583702158
1995	16.774039846024543
1996	15.338085031339382
1997	15.985368066037617
1998	15.144930442108803
1999	14.882777579121404
2000	14.768773125917031
2001	14.193604308367197
2002	13.439913714228977
2003	13.640018253565799
2004	12.006813855478232
2005	11.594486762683063
2006	11.176175516928106
2007	10.400864512062686
2008	9.943798689431071
2009	9.115310964583939
2010	9.851666346024517
2011	10.324023689690119
2012	10.559667129089204
2013	10.03069889375636
2014	10.415387010400112
2015	10.05151343719486
2016	10.273917688603367
2017	10.562463936408301
2018	10.076163225341618
2019	10.303776531270914
2020	8.736917076366602
2021	9.066934076538432
2022	10.279921543037247