Administration and asked the Secretary-General to appoint a committee to design the first United Nations stamps. An agreement was signed on 28 March 1951 between the United Nations and the United States Post Office Department which stipulated that the United Nations could start issuing postage stamps with two main provisions. First, that any stamps produced had to be denominated in United States dollars. Second, that these stamps could only be used at United Nations Headquarters. The Postal Service was formally inaugurated on United Nations Day in 1951, with its first set of stamps also going on sale that day. First stamps and collectivity The UNPA issued its first stamps for the New York offices in 1951. There was intense collector interest in the early issues, and a million stamps or more were sold of many of the early commemoratives. The scarcest item from this period, although still quite affordable, is the UN 10th anniversary souvenir sheet, Scott #38, of which 250,000 were printed. A precancel of the first 1½-cent stamp that was used on a number of mass mailings has been extensively forged. By 1957, the UNPA's commemoratives regularly sold out, though they might take several months to do so. Faced with this success, officials increased print runs from the usual million stamps to as many as five million. Surprisingly, sales increased tremendously, and sales of each commemorative stamp remained in the 1.5 to 3 million range through the 1970s. In 1967, the UNPA issued five stamps in Canadian dollar denominations for use at the United Nations pavilion at Expo 1967 in Montreal, Quebec. They became invalid when Expo 1967 closed. In 1968, the UNPA made an agreement with Swiss postal authorities, and on 4 October 1969 began to issue stamps in franc denominations for use at the Geneva offices. A 1979 agreement with Austria led to similar stamps for Vienna. There was a resurgence of interest in UN stamps in the 1970s, which may have peaked with the almost immediate sellout of the panes of 20 issued for the UNPA's 25th anniversary—three of the four denominations sold out on the date of issue (8 October 1976); the fourth sold out within two and a half months. A similar issue, in 1979, for the International Year of the Child sold out on the day of issue. The story made the front page of The New York Times. In 1980, the