Each person whose principal business is the selling of plate glass or other glass shall pay the following license tax: In cities of 100,000 inhabitants or more, $50; in cities or towns of more than 30,000 and under 100,000 inhabitants, $35; in cities or towns of more than 7,000 and under 30,000 inhabitants, $20; in all other places, $10.
Ala. Code § 40-12-107 (1975)