A penalty of 12 percent of all delinquent local improvement district assessments or installments thereof of the city heretofore or hereafter levied is fixed and charged. Such penalty shall become due on the date of delinquency of any such assessment or installment thereof, shall be added to the same, and shall be included in and become a part of the assessment lien, and shall be collected by the city in the same manner as all local improvement district assessments or installments thereof. (Ord. 3774 § 1, 1982; Ord. 3765 § 1, 1982; Ord. 3500 § 1, 1980; 1957 code § 8.04.050.)