The personal tax credit mentioned in the question is assumed to be the personal tax credit available to single, widowed and married persons as well as the additional tax credit for lone parents.
I am informed by the Revenue Commissioners that the projected number of tax cases liable to income tax at the 20% and 42% rates in 2005, assuming the continuation of the existing standard rate bands and personal tax credits, is estimated at 620,240 and 685,850 respectively.
Assuming increases of 10% on the credits and bands, it is estimated that these numbers would change to 685,750 and 581,030 respectively. A married couple, who has elected or has been deemed to have elected for joint assessment, is counted as one tax case. These figures are provisional, subject to revision and have been rounded to the nearest five as appropriate.