Year	% of expense
2000	54.83482211926031
2001	53.23552077332276
2002	52.070946087582705
2003	47.270069676180434
2004	46.302622136280846
2005	46.375446476932915
2006	52.6137192693233
2007	52.318596164796425
2008	45.94600157739444
2009	46.69097491484583
2010	46.55044146736797
2011	46.350068919764
2012	43.485418424650064
2013	43.97971043523928
2014	42.95353722387658
2015	42.28308856653752
2016	43.702208890100906
2017	40.373363640190256