92.045.  Certain cities may license, tax and regulate manufacturers, and other merchants, businesses and avocations — local legislative body may grant rulemaking power to tax official — copies of rules, where available (St. Louis City). — 1.  (1)  Any constitutional charter city in this state which now has or may hereafter acquire a population in excess of three hundred fifty thousand inhabitants, according to the last federal decennial census, is hereby authorized, for city and local purposes, to license, tax, and regulate the occupation of merchants, manufacturers, and all businesses, avocations, pursuits, and callings that are not exempt from the payment of licenses by law and may, by ordinance, base such licenses on gross receipts, gross profits or net profits, per capita, flat fee, graduated scale based on gross or net receipts or sales, or any other method or measurement of tax or any combination thereof derived or allocable to the carrying on or conducting of any business, avocation, pursuits or callings or activities carried on in such cities.

  (2)  Notwithstanding any provision of law to the contrary, no constitutional charter city in this state may license, tax, or regulate any enterprise owned by a person aged eighteen years or younger.

  2.  The local legislative body may grant by ordinance to its administering tax official the power to adopt regulations and rules relating to any matters pertaining to the administration and enforcement of any ordinances enacted in accordance with the authority heretofore given.  Copies of such regulations and rules shall be kept in the office of such tax official designated in such ordinance and shall be open to inspection by the public.  Said regulations or rules may be changed or amended from time to time.