Section 4B. The commissioner, each year, shall direct and cause the twenty-five admitted insurers with the largest homeowners market share in the commonwealth, based upon statewide written premium and the joint underwriting association, formed pursuant to the provisions of chapter one hundred and seventy-five C, to submit directly for his inspection and examination a tabulation and report, for each postal zip code within credit-eligible territories, as defined by chapter one hundred and seventy-five C, of all other postal zip codes in the city of Boston, and such other postal zip codes as may be designated by the commissioner of insurance, of the number of effected cancellations and number of effected non-renewals of homeowners policies covering properties within such zip codes; provided, however, that the personal privacy of policyholders shall be preserved and all tabulations furnished pursuant hereto shall be deemed materials described in subclause (c) of clause Twenty-sixth of section seven of chapter four.