Year % of revenue 1995 34.97144431503435 1996 38.16852545965469 1997 36.55233707215034 1998 37.647494645728294 1999 35.81183678930154 2000 36.980616570037775 2001 39.380951535719 2002 41.652054917122975 2003 39.52291914430312 2004 39.001224619414636 2005 36.01066497245823 2006 34.82984385387611 2007 35.5074837981839 2008 36.23194589818082 2009 36.142180903578975 2010 36.79251320264173 2011 34.73537012515527 2012 35.71020950096116 2013 36.055669582345146 2014 35.70627775648164 2015 33.920165096639934 2016 37.69454933260808 2017 40.6488476042418 2018 40.65923102984342 2019 40.75060408261039 2020 41.596055508559985 2021 40.89570286954665 2022 39.026245940789636