Every person engaged in a fixed place of business in the city in any trade, calling, occupation, or other means of livelihood and not as an employee of another and not specifically licensed by other sections of this article shall pay an annual license tax based upon the average number of employees employed in such business or thirty dollars for the first employee, four dollars each for the next nineteen employees, and three dollars for each additional employee above the twenty employees. The average number of employees shall be determined by ascertaining the total number of hours of service performed by all employees during each year and dividing the total by the number of hours of service constituting a year's work by one full-time employee, according to the custom governing such employments. (Ord. 338 § 22, 1975).