The act provides a new ten percent regular income tax bracket applicable to the first $6,000 of taxable income for single persons, $10,000 of taxable income for heads of households and $12,000 for married couples filing joint returns. The provision is made applicable for taxable years beginning after December 31, 2000. The $6,000 and $12,000 amounts increase to $7,000 and $14,000 respectively for 2008 and thereafter. The taxable income levels for the new low-rate bracket will be adjusted annually for inflation for taxable years beginning after 2008, and the bracket for single persons and married persons filing separately will be 50 percent of that of joint returns. Act. Sec. 101, amending I.R.C. § 1.