(a) Class 4. The following ZIP Codes are designated as Class 4 ZIP Codes: Attached Graphic(b) Class 3. The following ZIP Codes are designated as Class 3 ZIP Codes: Attached Graphic(c) Class 2. The following ZIP Codes are designated as Class 2 ZIP Codes:Attached Graphic(d) Class 1. The following ZIP Codes are designated as Class 1 ZIP Codes: Attached Graphic(e) Class 0. Any ZIP Code not listed in subsections (a)-(d) of this section are designated as a Class 0 ZIP Code. (f) Changes to designations. After initial designation of a ZIP Code, the designation may not be decreased (to a lower numbered class) for three years. Any such decrease in designation shall not be effective until one year after the changed designation is adopted as an amendment to this rule. An increase in the designation of a ZIP Code (to a higher numbered class) may occur at any time by amending this rule. (g) In designating ZIP Codes as Class 0, 1, 2, 3 or 4, the Commissioner shall use the share of average vehicles on policies in force in assigned risk and non-standard markets as a percentage of total average vehicles on policies in force by ZIP Code.