Discuss the basic trends over the past $30$ years regarding total wholesale sales for $($a$)$ Merchant wholesalers; $($b$)$ manufacturers'salesbranches and offices and $($c$)$ agents, brokers, and commission merchants.

The average size of retail units $($as measured by sales volume$)$ has been increasing. What are the implications of this trend for channel management in producing and manufacturing firms?

Discuss retailers 'growing power in the marketing channel in terms of the possible implications for channel management