international mail (blue), a system that remained in use for several decades. After the foundation of the United Nations, the UPU became a specialized agency of the UN in 1948. It is currently the third oldest intergovernmental organization after the Rhine Commission and the International Telecommunication Union. Terminal dues Origin The 1874 treaty provided for the originating country to keep all of the postage revenue, without compensating the destination country for delivery. The idea was that each letter would generate a reply, so the postal flows would be in balance. However, other classes of mail had imbalanced flows. In 1906, the Italian postal service was delivering 325,000 periodicals mailed from other countries to Italy, while Italian publishers were mailing no periodicals to other countries. The system also encouraged countries to remail through another country, forcing the intermediate postal service to bear the costs of transport to the final destination. Remailing was banned in 1924, but the UPU took no action on imbalanced flows until 1969. The problem of imbalanced flows became acute after decolonization, as dozens of former European colonies entered the UPU as independent states. The developing countries received more mail than they sent, so they wanted to be paid for delivery. In 1969, the UPU introduced a system of terminal dues. When two countries had imbalanced mail flows, the country that sent more mail would have to pay a fee to the country that received more mail. The amount was based on the difference in the weight of mail sent and received. Since the Executive Council had been unable to come up with a cost-based compensation scheme after five years of study, terminal dues were set arbitrarily at half a gold franc (0.163 SDR) per kilogram. Also since 1969, it announces the annual best postal services on the 9 October, the World Post Day. Modifications Once terminal dues had been established, they became a topic of discussion at every future Postal Union Congress. The 1974 Congress tripled the terminal dues to 1.5 gold francs, and the 1979 Congress tripled them again to 4.5 gold francs. The 1984 Congress increased terminal dues by another 45%. The system of terminal dues also created new winners and losers. Since the terminal dues were fixed, low-cost countries that were net recipients would turn a profit on delivering international mail. Developing countries were low-cost recipients, but so were developed countries like the United