The proceeds of the telephone cooperative gross revenue tax and the electric cooperative tax, less the amount expended by the state in their collection, shall be refunded to an organized borough or a city of any class incorporated under state law, in the proportion that the revenue was earned within the city or the borough area outside the city. However, taxes collected on gross revenue earned by a telephone cooperative or on the sale of electricity by an electric cooperative outside a city or organized borough shall be retained by the state and deposited into its general fund.