The annual fee for such licenses shall be two hundred fifty dollars ($250.00) plus fifty dollars ($50.00) for each mobile home over five (5) for which accommodations exist. If the number is increased, this shall be reported to the clerk, and the additional fee, if any, necessitated by such increase shall be paid before the additional spaces are put to use. When a license is applied for, or accommodations are increased during the license year, the fee shall be prorated on the basis of the number of months remaining in the license year. (1966 Code § 12.004)