Decade when ZIP codes were introduced

• Era of liberalization
• "Flower power" period
• "Peace" time?
• Hippie era, with 'The'
• Hippie decade
• The time of life between 60 and 70
• Great Society era, with "the"
• "Flower Power" era

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Sixty \Six"ty\, n.; pl. Sixties . The sum of six times ten; sixty units or objects. A symbol representing sixty units, as 60, lx., or LX.