(A) The sales factor is a fraction in which the numerator is the total sales of the taxpayer in this State during the taxable year and the denominator is the total sales of the taxpayer everywhere during the taxable year.
(B) The term "sales in this State" includes sales of goods, merchandise, or property received by a purchaser in this State other than the United States Government. The place where goods are received by the purchaser after all transportation is completed is considered as the place at which the goods are received by the purchaser. Direct delivery into this State by the taxpayer to a person designated by a purchaser constitutes delivery to the purchaser in this State.
(C) The word "sales" includes, but is not limited to:
(1) rentals from tangible personal property located in this State which are not separately allocated; and
(2) sales of intangible personal property and receipts from services if the entire income-producing activity is within this State. If the income-producing activity is performed partly within and partly without this State, sales are attributable to this State to the extent the income-producing activity is performed within this State.