Year % of revenue 1992 15.684622110183135 1993 16.83858273311951 1994 15.210662350852612 1995 14.137402011941079 1996 14.576427129850325 1997 11.46987587042083 1998 7.903489784066312 1999 9.122141344873164 2000 9.246815752875573 2001 7.4426266538481665 2002 8.24804341797282 2003 5.661005540277684 2004 6.953916296283399 2005 6.2924206717527955 2006 5.619138331053637 2008 6.342608820634149 2009 5.328572662405869 2010 4.516951915467227 2011 4.7209375352172005 2012 4.8235222862296885 2013 4.123711812129486 2014 4.0430058535827 2015 3.552493602577572 2016 3.496059066266067 2017 3.274173719674195 2018 3.722741284188638 2019 3.0122126955232917 2020 3.8747407149202973 2021 4.040507571840344 2022 3.0903336835103206