Year	% of expense
1995	35.87145338737695
1996	40.75337386919769
1997	40.820120284308366
1998	29.500756429652043
1999	29.851982196459993
2000	12.730465320456542
2001	15.114760216458295
2002	15.934209381254897
2003	13.558100424441418
2004	16.44852107595589
2005	16.623150565709313
2006	21.002290596174085
2007	33.41440345899203
2008	26.77896306288717
2009	18.735795454545453
2010	15.884970900376583
2011	16.376070074346362
2012	15.668842484567447
2013	13.202204087326496
2014	13.567223356962636
2015	14.1686268360253
2016	13.964604302819254
2017	14.623406094661767
2018	15.245874219446923
2019	14.186545604622369
2020	13.322440162566727
2021	13.85989975544202
2022	13.614622950458758