Year	% of revenue
1995	25.887608746766986
2002	23.29684352813931
2003	22.039431806619923
2004	19.233006371851772
2005	20.159473126293577
2006	18.669501656159717
2007	18.85434628991621
2008	18.480562129896438
2009	17.43171327804752
2010	15.608732727377744
2011	16.85448320002572
2012	14.587250748366154
2013	15.478155064004758
2014	17.163439563676288
2015	16.730103663117042
2016	15.411075567058486
2017	16.635904153519117
2018	17.17830201095963
2019	18.163452436106983
2020	17.924634044104945
2021	19.26872086866637
2022	18.126793824364697