Title: Tax revenue: a key concept in Economics
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Content: regressive taxes, with falling tax rate whilst increasing base; 4. lump sum taxes, with a fixed absolute value of the tax, irrespective of the tax base. Thus, the income distribution and tax base dynamics are key determinants for the revenue from progressive, proportional and regressive taxes, whereas it becomes irrelevant for lump sum taxes. Fiscal systems differ a lot throughout the world but usually the personal revenue tax is progressive, the firm revenue tax is proportional as well as the taxation of domestic and international economic activity. Also wealth taxation is usually proportional, with some use of lump sums. Lump sums are particularly common for taxes of a small absolute value. Progressive taxes have the advantages of producing a large revenue from a small number of taxpayers, which are in political minority. Their political acceptance in selfish voters can thus be high. Taxes on what is considered as "bad" (e.g. pollution, smoking, drinking alcohol) are also more justifiable from a moral point of view (and offer to the "good-habit" people the possibility of escaping the tax), so usually they are politically sustainable.