A school district may choose not to increase its property tax request by the full amount allowed by the school district's property tax request authority in a particular year. In such cases, the school district may carry forward to future years the amount of unused property tax request authority. The department shall calculate each school district's unused property tax request authority and shall submit an accounting of such amount to the school board of the school district. Such unused property tax request authority may then be used in later years for increases in the school district's property tax request.