Year	% of expense
1999	18.96055555613545
2001	20.39712992980606
2002	21.136117155940145
2003	21.06757193697948
2004	21.09770771304634
2005	23.000835314452207
2006	22.44277476795974
2007	24.141145907707855
2008	21.480882559285718
2009	22.91503103863962
2010	23.07871134876838
2011	22.935371102335232
2012	23.289090465168414
2013	21.469334940266513
2014	22.15955387191525
2015	23.474664942950234
2016	23.56080978257549
2017	22.9139379985175
2018	23.215951888593455
2019	23.517868425651777
2020	21.471914135389746
2021	20.472257803556886
2022	19.034609730592507