If the prevailing price or value of goods regularly bought and sold in an established commodity market is in issue, reports in official publications or trade journals or in newspapers or periodicals of general circulation published as the reports of that market are admissible in evidence. The circumstances of the preparation of such a report may be shown to affect its weight but not its admissibility. Reports are also admissible under rule of evidence 5.803(17).
Iowa Code § 554.2724
83 Acts, ch 37, §2