When will tax reform now being considered by Congress be effective?

Progressivity in income tax is accomplished mainly by establishing tax "brackets" - tranches of income that are taxed at progressively higher rates. For example, for tax year 2006 an unmarried person with no dependents will pay 10% tax on the first $7,550 of taxable income. The next $23,100 (i.e. taxable income over $7,550, up to $30,650) is taxed at 15%. The next $43,550 of income is taxed at 25%. Additional brackets of 28%, 33%, and 35% apply to higher levels of income. So, if a person has $50,000 of taxable income, his next dollar of income earned will be taxed at 25% - this is referred to as "being in the 25% tax bracket," or more formally as having a marginal rate of 25%. However, the tax on $50,000 of taxable income figures to $9,058. This being 18% of $50,000, the taxpayer is referred to as having an effective tax rate of 18%.