The percent of the lot area covered by structures shall be measured by dividing the total number of square feet of horizontal ground area covered by structures, open or enclosed, whether located on a private lot or on any adjacent City-owned property, by the total horizontal area of the lot (not including any adjacent City-owned land), provided that the area of uncovered and unenclosed off-street parking spaces, walks, patios, trellises, in-ground swimming pools or pools that do not project more than four feet above the average ground level, uncovered decks or garage aprons four feet or less above the average ground level shall not be counted in the total coverage, and provided that only one-half of the area of uncovered and unenclosed decks or balconies fifteen or more feet above the average ground level shall be counted in the total coverage. Notwithstanding the above, in residential zones, the area of all covered off-street parking shall be included in the total coverage. (Ord. 92-8 § 14, 1992; Ord. 91-5 § 2, 1991; Ord. 89-1 § 1, 1989.)