Table 2 4-Firm concentration ratio and Herfindahl-Hirshman index by year, 1960-1970

Household vacuum cleaner (SIC: 3635)

Year - 1963:

81 %

1966:

78

1967:

76

1970:

79

Cooking appliances (SIC: 3631)

1963:

51 %

1966:

54

1967:

56

1970:

61

Refrigerator and home freezer (SIC: 3632)

1963:

74 %

1966:

72

1967:

73

1970:

82

Laundry equipment (SIC: 3633)

1963:

78 %

1966:

79

1967:

78

1970:

83