In this chapter, the following terms have the meanings indicated. Terms Defined. “Affidavit” means a sworn statement in writing on a standard form furnished by the Department. “All persons who are actual occupants of the dwelling” means household residents during the calendar year for which a credit is sought. “Applicant” means a person filing for a property tax credit. “Combined gross income of all persons” means the monies received in the prior year by the applicant renter, the spouse, unless separated, divorced, or widowed, or the resident co-tenant, or all of these, and the monies received by other nondependent occupants of the household unless they are paying reasonable fixed charges to the applicant renter. “Combined net worth” means the net worth of the applicant, spouse or co-tenant, or all of these, residing in the dwelling unit. “Dependent” means a person who satisfies the federal Internal Revenue Service standard for a dependent. “Dwelling unit” means the principal residence of a renter and may be any type of apartment, an individual house, a duplex, a co-op or condominium, or a house trailer or trailer pad. “Principal residence of the renter” is the one dwelling unit where the renter regularly resides and is the location designated by the renter for the legal purpose of voting, obtaining a driver's license, and filing income tax returns. “Leasehold interest” means a tenancy in the dwelling unit held under a written lease. “Persons 60 years old or older” means a person who reached that age as of December 31 of the year for which a credit is sought. “Reasonable fixed charges” means the amount of room and board, rent, or expenses paid which are sufficient to defray the cost of a person residing on the premises. “Reasonable value of utilities” means the cost of providing heat, gas, or electricity for the dwelling unit. “Total income” means all monies received by a person in a calendar year, whether taxable for federal or State income tax purposes or not.