In order to determine whether a sale or service is recognized as a
retail sale or service in the ``particular industry'' it is necessary to
identify the ``particular'' industry to which the sale or service
belongs. Some situations are clear and present no difficulty. The sale
of clothes, for example, belongs to the clothing industry and the sale
of ice belongs to the ice industry. In other situations, a sale or
service is not so easily earmarked and a wide area of overlapping
exists. Household appliances are sold by public utilities as well as by
department stores and by stores specializing in the sale of such goods;
and tires are sold by manufacturers' outlets, by independent tire
dealers and by other types of outlets. In these cases, a fair
determination as to whether a sale or service is recognized as retail in
the ``particular'' industry may be made by giving to the term
``industry'' its broad statutory definition as a ``group of industries''
and thus including all industries wherein a significant quantity of the
particular product or service is sold. For example, in determining
whether a sale of lumber is a retail sale, it is the recognition the
sale of lumber occupies in the lumber industry generally which decides
its character rather than the recognition such sales occupies in any
branch of that industry.