Year % of tax revenue 2002 8.896619198737612 2003 11.88595850592327 2004 8.329099727077823 2005 4.756429024718356 2006 4.777523064219982 2007 4.1529320050747005 2008 2.6099452835000743 2009 2.776153567495348 2010 2.526384164195777 2011 3.5563700260862094 2012 2.6922054176437333 2013 2.9414183925823645 2014 2.285215605924858 2015 1.6833734766704551 2016 0.26039221790464295 2017 0.32088872496181503 2018 0.3032371049632646 2019 0.22470408547684695 2020 0.12570399894607995 2021 0.24065961130426342