Centennial Period
The tag shown above was attached to a diplomatic pouch mailed from the Embassy of the United States of America in Ottawa to the Secretary of State, Washington, D.C. on March 8, 1972. The regulations of the Postal Union of the Americas and Spain, to which both the United States and Canada belonged, provided that diplomatic mail of this type could be forwarded free of postage unless dispatched by air mail.
Although there is no air mail label on the tag, the payment of $6.20 postage indicates that air mail service was to be provided :
$6.20 likely paid the air mail letter rate (10 cents per ounce) for 62 ounces.