Year	% of expense
2002	19.322242357440743
2003	17.125739217929812
2004	19.095000876985385
2005	19.0638289902394
2006	21.7194629141649
2007	24.561509004882648
2008	22.78787568536378
2009	20.664981932147082
2010	20.62132873928459
2011	24.35893762713807
2012	31.330475728459962
2013	29.52017895605711
2014	21.413068921026902
2015	21.84730784717268
2016	19.656744435505498
2017	12.141443922023589
2018	8.231696398637576
2019	10.716176031151235
2020	6.815109759131421
2021	4.154435959137886
2022	1.9307993809804616