Year % of tax revenue 1994 8.353329114902131 1995 8.555744654193118 1996 19.64531439933188 1997 8.932601336047037 1998 12.83681745953881 1999 11.77447593180623 2008 3.603398573812775 2009 4.0878499462387 2010 4.2167041140466415 2011 3.6297099059196785 2012 3.2806804374240586 2013 3.819194823867721 2014 4.354150273028591 2015 4.550383028874484 2016 6.803711115153719 2017 7.571846683874591 2018 8.435885394011388 2019 9.472120363770642 2020 9.138584934763278 2021 9.576228505647888