Year	% of expense
1995	69.9140377249916
1996	70.92669120993433
1997	71.66745700950908
1998	72.24958218132798
1999	73.12385434308763
2000	73.26004041875218
2001	74.14776248370507
2002	74.94699643522881
2003	75.65313598866204
2004	77.90785700693844
2005	73.70337768649296
2006	78.23965585297685
2007	78.96020546569962
2008	79.70174611685167
2009	80.50933013498711
2010	80.66176781887954
2011	80.40502265581023
2012	79.42883731423254
2013	81.27781531663702
2014	81.08480009843741
2015	81.66510120859517
2016	82.68939086809617
2017	83.41662819188392
2018	84.18616182227828
2019	84.58356293601351
2020	85.29639989350872
2021	85.74144423188602
2022	84.9936673533572