Excerpt from the report: Frozen food locker plants operating In the United States in January 1957 totaled 9,894. Iowa again led with 702, Washington came second with 650, and Wisconsin third with 606. As compared with the previous year this represents a decline of 430 plants. Over half of this decline took place in five midwestern States -- Iowa, Minnesota, Missouri, Nebraska, and Ohio and consisted largely of small plants many of which were operated as side lines with other business enterprises such as creameries, retail stores and ice companies.