The attorney shall file a sworn statement with the department showing the maximum amount of indemnity upon any single fire insurance risk. The attorney shall also file, whenever required, a sworn statement with the department that he has examined the commercial rating of the subscribers as shown by the reference book of a commercial agency having at least one hundred thousand subscribers and that from this examination or other information in his possession it appears that no subscriber has assumed more than ten percent of its net worth on any single fire insurance risk.