In this chapter, the following terms have the meanings indicated. Terms Defined. “Property factors” means data that measure the physical presence of the operating unit within the State. Examples of property factors include such items as property cost and miles of track. “Revenue factors” means data that measure the economic activity of the operating unit within the State. Examples of revenue factors include such items as gross revenue and net operating income. “Use factors” means data that measure the physical activity of the operating unit within the State. Examples of use factors include such items as ton mileage and originating and terminating tons of freight. In allocating a portion of the operating unit to the State, the Department may use a combination of property, revenue, and use factors. The factors used shall be sufficient to produce a reasonable estimate of the unit value attributable to the State. Tax-Property Article, §§2-201 and 8-108, Annotated Code of Maryland Effective date: July 22, 1991 (18:14 Md. R. 1610)