Year % of tax revenue 1998 8.528437548323387 1999 6.71987207455364 2000 7.454470000670666 2003 6.41641087200752 2008 8.881993157503455 2009 7.204762138079763 2010 8.299417032804877 2011 5.72921569174431 2012 5.0234770046091475 2013 4.279985914842682 2014 3.274101142694611 2015 3.6498273421263376 2016 3.255440189280292 2017 2.7744842331798933 2018 2.465573561488527 2019 2.426625977827933 2020 2.0919979226567844 2021 2.5845397670781454 2022 2.7871140518036968