Year	% of expense
1998	38.01083596389755
1999	40.6240842401391
2009	31.14587247157078
2010	31.10656772383195
2012	40.84713441255172
2013	37.786358711275234
2014	31.362383163193403
2015	33.742539313306914
2016	36.834633009084335