354 Chapter 9 OligopolyTABLE 9.1
Concentration Ratios
for Selected Goods &
ServicesConcentration Ratio
Product or Service 4 Firms 8 Firms 20 Firms
Laundry machines 98 100
Warehouse clubs 94 100
Refrigerators 92 98
Web Search 91 95
Aluminum refining 90 99
Beer 90 92
Tobacco 90 95
Glass containers 87 95
Rental cars 87 96
Personal computers 87 92
Carbon black 84 99
Cellular phone service 82 94
Aircraft 81 94
Breakfast foods 80 92
Office supply stores 80 81
Ammunition 79 89
Tires 78 93
Running shoes 77 96
Metal cans 77 95
Aircraft engines 74 81
Burial caskets 74 83
Bottled water 72 85
Vacuum cleaners 71 96
Bookstores 71 78
Lawn equipment 71 84
Flat glass 70 98
Stockings 69 85
Motor vehicles 68 86
Domestic air flights 65 83
Motion pictures 64 96
Drug stores 63 66
Cable television 62 79
Photocopying machines 61 83
Farm machinery 59 65
Men’s shoes 57 82
Elevators 56 70
Snack foods 53 61
Nuclear power 53 76
Investment banking 52 77
Oil refining 48 73
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