One real estate sign not exceeding twelve (12) square feet in area may be located on each street frontage of a building, parcel, or lot. However, where a building contains leasable or salable ground floor space, one real estate sign may be placed for each leasable or salable ground floor space in lieu of the one real estate sign normally allowed for each street frontage of the building, parcel or lot. The real estate signs so placed may contain a minimum total area of twelve (12) square feet, but where the street frontage of the building, lot or parcel exceeds one hundred twenty (120) linear feet, the real estate signs advertising leasable or salable ground floor space may contain a total of up to one square foot per ten (10) lineal feet of frontage. No such sign shall be located except as provided for herein. (Ord. 80-O-1775, eff. 12-5-1980; amd. Ord. 91-O-2119, eff. 7-5-1991)