Year % of revenue 2010 4.684051102548846 2011 5.2502846055409735 2012 5.476772108541988 2013 5.63903702693068 2014 6.73654293588252 2015 7.24262453652013 2016 7.128243821148775 2017 5.51734500328828 2018 6.6013711713498955 2019 5.343231948254077 2020 5.758912208009312 2021 6.172469911376317 2022 5.351432629225404