Year % of revenue 2005 5.574837310195227 2006 4.613516433475897 2007 4.028153161029006 2008 2.939065035032046 2009 2.6410167959282242 2010 1.7978016297682995 2011 1.2535138622927628 2012 1.0373342427655565 2013 1.5711978081855376 2014 1.8366937814760453 2015 2.8359493994746794 2016 3.1136292907012253 2017 3.46609727482339 2018 3.849641653062277 2019 3.92408959297592 2020 6.434244921897441 2021 6.645793416772556 2022 7.239902618272363