Year	% of expense
2003	27.7382228074391
2004	29.03627547048263
2008	31.882073117777004
2009	29.88093646517671
2010	32.09185191482127
2011	34.00584094248524
2012	32.09034017290329
2013	32.0747261437432
2014	32.34877497087901
2015	32.59707046313085
2016	31.80672372049937
2017	30.997915327277966
2018	30.893049588732037
2019	28.636400572276195
2020	31.634242094734745
2021	31.21448463337539