Year	% of expense
1998	14.857793646885003
1999	14.332289067063133
2000	14.361234817378826
2003	13.540416857790882
2004	13.093836787265154
2005	14.900800471443304
2006	14.514670322618214
2007	14.196045244360949
2008	15.204906768505259
2009	13.837586139884841
2010	12.801765996600295
2011	13.899772642428918
2012	16.150237565246815
2013	15.667726362842256
2014	14.184788477448821
2015	14.313767551883283
2016	11.916174387082588
2017	13.090678751232495
2018	12.057925403789284
2019	10.659429352732364
2020	11.397971487339529
2021	14.359230509155868
2022	13.360865285379052