Year	% of expense
2000	7.992007992007992
2001	5.218553745742054
2002	5.800334810686804
2003	5.311874964299238
2004	4.47398778058461
2005	4.414320464428971
2006	3.164128218792047
2007	2.7483313702394976
2008	2.6768391499851636
2009	2.496870251327269
2010	2.829538326804502
2011	4.076520458631894
2012	3.5306659751309764
2013	4.447871869174403
2014	4.536999682849578
2015	5.452481790473963
2016	4.318093005080109
2017	6.67622546823192
2018	7.158438874856467
2019	7.991067297226068
2020	8.480182723175723