"cost of living" means the sum of money required to provide for the following categories of household expenditures for a household of three persons, with a household income as may be determined from time to time by the Minister:
shelter,
food,
clothing,
furniture and other household items,
personal care,
medical and dental care,
domestic services, including childcare,
recreation,
transportation,
income tax,
sales tax, and
"marginal tax rate" means the second from the lowest personal federal tax rate combined with the applicable provincial or territorial tax rate without any surcharge or reduction. (taux marginal d'imposition)