Year	% of expense
2001	36.6291472244949
2002	37.79786535772381
2003	36.95343942929444
2004	32.97112172846814
2005	31.47805498311922
2006	21.73123858238948
2007	26.256244358852914
2008	21.489683156349823
2009	25.567438236146216
2010	24.102061522852004
2012	24.246234436104423
2013	27.10156511017054
2014	24.512133674692233
2015	28.577423781231065
2016	32.260551385489435
2017	30.87630632976362
2018	32.87432672566302
2019	32.13414368698292