The U.S. government formed the Congress of Micronesia in 1965, a plan for increased self-governance of Pacific islands. The Trust Territory of the Pacific Islands in May 1979 provided independence to the Marshall Islands, whose constitution and president (Amata Kabua) were formally recognized by the US. Full sovereignty or self-government was achieved in a Compact of Free Association with the United States. Marshall Islands has been a member of the Pacific Community (SPC) since 1983 and a United Nations member state since 1991. Politically, the Marshall Islands is a parliamentary republic with an executive presidency in free association with the United States, with the U.S. providing defense, subsidies, and access to U.S.-based agencies such as the Federal Communications Commission and the United States Postal Service. With few natural resources, the islands' wealth is based on a service economy, as well as fishing and agriculture; aid from the United States represents a large percentage of the islands' gross domestic product but most financial aid from the Compact of Free Association expires in 2023. The country uses the United States dollar as its currency. In 2018, it also announced plans for a new cryptocurrency to be used as legal tender.