Year % of tax revenue 2000 15.257625385439097 2001 13.521205196095435 2002 13.090634306796462 2003 16.19053806051354 2004 14.657994640996755 2005 15.525228551126474 2006 15.714320468940176 2007 15.998832727478138 2008 14.911951236339318 2009 12.9433656807456 2010 13.619218984040455 2011 13.825099686149903 2012 13.699111741704186 2013 11.534723090598751 2014 11.868939927791287 2015 0.4379242391066345 2016 0.5176680091523704 2017 0.6101157186146307