Year % of tax revenue 2005 24.44779024850086 2006 26.922847662381532 2007 27.95801526717557 2008 31.22439482810515 2009 1.3990126157790712 2010 27.371053809155 2011 29.185674244057076 2012 27.91370975914666 2013 28.987916610903685 2014 29.858283290288522 2015 31.677837432770506 2016 31.362539152361503 2017 34.51082927866015 2018 37.75203672765248 2019 36.0437119254436 2020 40.5641704873378 2021 44.01174212934271