Year	% of tax revenue
1990	0.35084698336167375
1991	0.23181686467690527
1992	0.030282637954239567
1993	0.006711184188450053
1994	0.006474482446059469
1995	0.006539366989275437
1999	0.0036983160334327775
2005	0.6124508487749829
2006	0.5413418872048498
2007	0.4531745619334547
2008	0.032704847207691866
2009	1.398900548207707
2010	0.5585182412415968
2011	1.570258559076454