Each insurer shall maintain at its home or principal office a complete file containing every printed, published, or prepared advertisement of its individual policies and typical printed, published, or prepared advertisements of its blanket, franchise, and group policies hereafter disseminated in this or any other state whether or not licensed in such state, with a notation attached to each such advertisement which shall indicate the manner and extent of distribution and the form number of any policy advertised. Such file shall be subject to regular and periodical inspection by the insurance commissioner. All such advertisements shall be maintained in said file for a period of either four years or until the filing of the next regular report on examination of the insurer, whichever is the longer period of time.