In a Class I Residential, Class II Residential or Class III Residential District, every building erected shall have a rear yard. The least dimension of a rear yard shall be not less than fifteen percent of the depth of the lot. However, in the case of any building more than two and one-half stories in height, such least dimension shall not be less than one-half the height of the building. Such least dimension need not be more than twenty-five feet in any case.
(1956 Code Sec. 1319.06)