From Phillip Howard of MSU:

Three firms control 89% of US soft
drink sales [1]. This dominance is obscured from us by the
appearance of numerous choices on retailer shelves. Steve Hannaford
refers to this as "pseudovariety," or the illusion of diversity,
concealing a lack of real choice [2]. To visualize the extent of
pseudovariety in this industry we developed a cluster diagram to
represent the number of soft drink brands and varieties found in
the refrigerator cases of 94 Michigan retailers, along with their
ownership connections.