Year	% of revenue
2001	15.382833094602749
2002	13.24359055827314
2003	11.310209240275242
2004	11.250141593738501
2005	11.458877284595301
2006	12.473083702783054
2007	11.343817593522116
2008	10.215768568170137
2009	9.02447688247227
2010	7.7471842257740615
2011	7.427228541989206
2012	8.133321748098368
2013	6.693664962033857
2014	7.843338183587877
2015	9.09138065346699
2016	9.623074851352978
2017	8.6985375867947
2018	6.737251356529931
2019	8.553280754437411
2020	9.050414381650468
2021	9.806353326793165