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Behind the Scenes: 1968:
Codes and machines revolutionized the Postal Office in the 1960s. The ever-growing volume of mail drove the Post Office to introduce ZIP Codes. Machines began taking on more and more of the work of moving the mail. Postal workers using these machines could sort 30,000 letters an hour.
Since then, the pace and scale of automation in the postal system has exploded.
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