Year	% of expense
1998	48.97348023361469
1999	49.25920891667799
2000	50.182015140636615
2001	53.005117574658286
2002	53.33748686750226
2003	53.56903711688143
2004	45.80019851696152
2005	39.18323183665594
2006	41.16979888050676
2007	39.729801298946285
2008	36.967311088733396
2009	37.65361555057679
2010	39.34821362996001
2011	35.59074544951034
2012	30.68802825217768
2013	30.289762877908366
2014	33.56432606498128
2015	39.00147482508145
2016	36.05427343801818
2017	36.20937236255592
2018	33.58038977583451
2019	34.46720086854435
2020	16.688799532377807
2021	15.234805121028522